The Effect Of Speed Limits On Actual Travel Speeds
By Jim Walker, NMA Michigan Member
I have worked closely with the Michigan State Police for several years in their pursuit of correcting as many Michigan posted speed limits to the correct 85th percentile speed level as possible. Yes, we have a very enlightened state police administration that wants to see posted limits set for safety, not revenue.
I have testified before Michigan legislative committees in support of the State Police to help explain the science involved, helped to nominate the key officers for a Governor’s Traffic Safety Advisory Committee Award which they won in 2006, and helped the police find areas of state trunk line routes (numbered highways) which should be re-surveyed because the posted limits were set far below the normal speeds of traffic.
In late 2006, the state police came to Ann Arbor and did speed studies on several state routes through Ann Arbor, parts of Business Route US-23 and parts of Business I-94. The posted limits on these trunk line routes are legally under the control of the state police and MDOT, not local authorities, but the local authorities can sometimes “push back” in the court of public opinion.
After a long period of negotiations and explanations with a city that does not want posted limits raised at all, three areas were re-posted in early 2008 with corrected speed limits raised to the 85th percentile speed of free flowing traffic under good conditions.
The City Council even passed a resolution opposing these safety-oriented changes, but they do not have legal control over state routes, so they finally agreed to the three areas to be changed.
After allowing a period of adjustment while drivers got used to the newly posted higher limits, I re-surveyed these three areas to see what changes there were, if any, in actual travel speeds.
The huge study done in 1992 by Martin Parker says there would be little change in the speeds people actually drive.
This was, of course, the result.
Actual travel speeds changed by a maximum of 2 mph in some parameters, not at all in others, and some speed points were lower with the higher posted limits. The actual traffic speeds remained the same as they have been for 23 years.
One thing did change. As was expected, the vast majority of safe, sane, competent drivers who go along with the normal flow of traffic are no longer arbitrarily defined as criminals, and no longer subject to big ticket fines and even bigger insurance surcharges.
One of my key goals is to get a reluctant Ann Arbor city government to adopt the proven practices to set the safest speed limits as described in the Institute of Transportation Engineers Engineering Handbook, the Michigan Manual of Uniform Traffic Control Devices, and the revised set of Michigan traffic laws that went into effect in November of 2006.
It is an uphill battle, because of two reasons.
First, the city makes so much money from traffic tickets that safety practices take a back seat to the revenue.
Second, the flow of misinformation and deliberate disinformation that has come out of Washington since the early 1970s has convinced many citizens that lower numbers painted on the speed limit signs means lower actual traffic speeds and safer driving.
Anyone who has read the scientific literature knows this is totally false, but a lot of education is needed to repair the damage and correct the false beliefs many people have about posted limits.
Hopefully the City Council members and others who read the charts will see the proofs that actual travel speeds do NOT rise with corrected 85th percentile posted speed limits and that will remove one counter argument for posting 85th percentile speed limits to maximize safety.
RESULTS
Definitions included at the bottom of the page.
History Of Speeds On North Main Street (Northern Section)
Data is from the middle of the section where the posted speed limit was corrected to 45 mph in 2008, from the former 40 mph. Data is taken at Points 1 and A on the MDOT Traffic Control Order Map.
|
Survey Date |
Sep 2006 |
Aug 2008 |
|
Posted Speed Limit |
40 MPH |
45 MPH |
|
% of Vehicles Obeying Speed Limit |
33% |
71% |
|
50th Percentile Speed |
43 MPH |
43 MPH |
|
85th Percentile Speed |
47 MPH |
47 MPH |
|
90th Percentile Speed |
49 MPH |
49 MPH |
|
% of Vehicles at 50 MPH or Higher |
8.4% |
8.6% |
|
Fastest Speed Recorded |
55 MPH |
54 MPH |
|
Total Range of Speeds |
29 to 55 MPH |
33 to 54 MPH |
|
Maximum Difference in Speed |
26 MPH |
21 MPH |
History Of Speeds on Washtenaw Avenue, Near the City Club
Data is from the middle of the section where the posted speed limit was corrected to 40 mph in 2008, from the former 30 mph. Data is taken at Points 5 and P on the MDOT Traffic Control Order Map.
|
Survey Date |
Sep 2006 |
Aug 2008 |
|
Posted Speed Limit |
30 MPH |
40 MPH |
|
% of Vehicles Obeying Speed Limit |
8% |
86% |
|
50th Percentile Speed |
35 MPH |
36 MPH |
|
85th Percentile Speed |
40 MPH |
40 MPH |
|
90th Percentile Speed |
41 MPH |
42 MPH |
|
% of Vehicles at 45 MPH or Higher |
0.7% |
1.7% |
|
Fastest Speed Recorded |
47 MPH |
49 MPH |
|
Total Range of Speeds |
28 to 47 MPH |
28 to 49 MPH |
|
Maximum Difference in Speed |
19 MPH |
21 MPH |
History Of Speeds on Washtenaw Avenue, Ann Arbor, Michigan
Data is from the middle of the section where the posted speed limit was corrected to 45 mph in 2008, from the former 35 mph. Data is taken at Points R & S on the MDOT Traffic Control Order Map.
|
Survey Date |
Sep 2006 |
Aug 2008 |
|
Posted Speed Limit |
35 MPH |
45 MPH |
|
% of Vehicles Obeying Speed Limit |
4% |
79% |
|
50th Percentile Speed |
42 MPH |
43 MPH |
|
85th Percentile Speed |
47 MPH |
46 MPH |
|
90th Percentile Speed |
48 MPH |
47 MPH |
|
% of Vehicles at 50 MPH or Higher |
4.7% |
2.6% |
|
Fastest Speed Recorded |
58 MPH |
52 MPH |
|
Total Range of Speeds |
33 to 58 MPH |
34 to 52 MPH |
|
Maximum Difference in Speed |
25 MPH |
18 MPH |
DEFINITIONS:
50th Percentile: Speed at which 50% of vehicles are above that speed and 50% are below.
85th Percentile: Speed at which 85% of the vehicles are below or right at that speed.
90th Percentile: Speed at which 90% of the vehicles are below or right at that speed.
Update (8/24/08) – The story was picked up by the media in Ann Arbor:
Speeding ticket challenge upheld in Washtenaw County Circuit Court
A better traffic flow? Ann Arbor man says so
Other Related Articles
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So why does Mr Walker advocate allowing speeds that are equally as likely to cause a crash as the speeds he claims are so unsafe that we must raise the limit up and away from to post at the 85th percentile speed. Mr Walker and I agree that setting the speed limits in the area of the lowest point along the crash incidence curve would generate safety benefits. where we disagree is that I recognize that as speed above that point increases the safety benefits decrease and I conclude that the closer we can keep traffic to that lowest point on the risk curve the greater the safety benefits we will experience. Mr Walker believes in perverting the science and quoting this a way to increase safety so that he can then demand an enforcement grace above that and get an even higher allowable speed to drive. Think about what Mr Walker has told you that he wants to allow. He wants to allow speeds upto and beyond the 95th percentile speed even though he admits that the safest point on the risk curve is at the 85th percentile. WHY?
Again you mis attributed my position. Big surprise that a member of the NMA would twist something that I offered to advance their agenda.
[...] Study after study (they are called before and after speed studies) have shown that the actual posted speed limit (that black and white sign on the side of the road) has very little effect on actual measured operating speeds. [...]
Mr Walker told me he was done some months ago but we all see how much his word is worth. My only message to the readers here is that they should read the studies and traffic engineering works for themselves and NOT believe the lies that the NMA Mr Walker or Mr Young tell them. Draw your own conlusions based upon what you read and don't be pressured by the NMA, Mr Walker or Mr Young to draw any specific conclusion.
I told Mr. Mckrackin last night that we were done. Among other comments I said:
"I am done with Mr. Mckrackin. His baseless accusations have made me unwilling to reply further. If someone else wishes to deal with this nonsense, they are welcome to do so."
I sent a more gentle message via private email and again thanked him for the most complete debate I have ever had on these issues.
If someone else wishes to continue with Mr. Mckrackin, they are welcome to do so. If I see something where I might add some facts, figures or references in response to someone else communicating with Mr. Mckrackin, I may chime in to respond to the person debating Mr. Mckrackin. But I will no longer be debating Mr. Mckrackin directly – either here on on private email.
The baseless accusations and personal attacks became too much to ignore.
It is amazing how people who call others liars, corrupt, ignorant, clueless and unknowing get upset when you do the same back to them.
So why does Mr Walker advocate allowing speeds that are equally as likely to cause a crash as the speeds he claims are so unsafe that we must raise the limit up and away from to post at the 85th percentile speed. Mr Walker and I agree that setting the speed limits in the area of the lowest point along the crash incidence curve would generate safety benefits. where we disagree is that I recognize that as speed above that point increases the safety benefits decrease and I conclude that the closer we can keep traffic to that lowest point on the risk curve the greater the safety benefits we will experience. Mr Walker believes in perverting the science and quoting this a way to increase safety so that he can then demand an enforcement grace above that and get an even higher allowable speed to drive. Think about what Mr Walker has told you that he wants to allow. He wants to allow speeds upto and beyond the 95th percentile speed even though he admits that the safest point on the risk curve is at the 85th percentile. WHY?
Quote of Mr Walker "This is playing with words, but worth a reply. We know that setting limits at the 85th tends to produce the lowest crash rate. We know that limits a bit below the 85th tend to have a slightly higher crash rate and those set way below the 85th tend to have even higher crash rates. So, does correcting a low limit to the correct 85th level raise safety? Yes, in my view, and for precisely the reasons Mr. Mckrackin states – more vehicles at like speeds and fewer speed variations. We should add – this improved speed distribution with fewer variances tends to reduce the conflicts between vehicles and THAT is where the improved safety really comes from. " If speeds sligthly lower than the 85th tend to have slightly higher crash rates and those set way below the 85th tend to have even higher crash rates and the crash incidence curve is a "U" shape with speeds slightly above the 85th experiencing slightly higher crash rates and as the speed increases above the 85th so too does the crash rates associated with those speeds….cont….
There is no misquote on my part. Mr Baxter tells us that the 90th percentile is the point where speeds become unreasonable and that those drivers traveling at those speeds will experience far more crashes. I realize that Mr Baxter's use of ambiguos terms is probably purposefule so that Mr Walker and other NMA members can speak in defense of his comments. The risk curve goes UP after the mean speed on several crash incidence curves I have examined. Mr Walker tries to replace that with the 85th and suggest that the lowest point of risk is AT the 85th percentile. It is NOT!
Here is a comment made by an NMA member in an editorial article on this site.
"According to an Institute of Transportation Engineers Study, those driving 10 mph slower than the prevailing speed are six times as likely to be involved in an accident."
Note that the intellectual dishonesty where he implies that faster is safer. This member fails to also attribute that speeds of less than 10mph above the prevailing speed are just as likely to result in a crash and a crash of exponentially greater severity. At speeds above 37mph, for every 3mph you increase your speed you double your risk of injury and/or death. Notice how many times that risk would double from 10mph below the prevailing speed to the prevailing speed and then how many times that risk would double again upto the point on the crash incidence curve where crashes are just as likely to occur as 10mph below the prevailing speed. according to my math that means that 10mph above the prevailing speed has about an equal chance to result in a crash as 10mph below the prevailing speed by 64 times as much chance to result in injury or death.
I see the NMA has returned to censor these posts!
If A speed limit was set at 65mph as a corrected 85th percentile speed limit and you knew that you could drive at upto 75mph without being ticketed how fast would you drive?[polldaddy 2740542 http://answers.polldaddy.com/poll/2740542/ polldaddy]
The poll is interesting, but of course NOT representative of the speed distribution you would get in a survey. I answered 1-4 above, my usual speed range, just above the 85th. I would be in the roughly 8% to 10% of the whole speed distribution that is above the 85th, but in the next 5 interval.
The people who answered 5-9 over are in the target zone for enforcement under my method and are roughly the top 5%. There would be VERY few people 10 or more over a true 85th limit, typically 1% or so. Both of these groups are pretty easy for an officer to target with a correct 85th limit. There are not so many of them, they are a lot more likely to be free-flowing & alone in the left lane, and the lane discipline on a multi-lane road that is posted correctly is much better — so they are a lot less likely to be blocked by a lane hog.
Quote from Jim Baxter NMA president((The ensuing expansion of speed limits was not a smooth and seamless process, but from it came research that is just as valid today as it was in the 1950's. The vast majority of drivers can be expected to travel at safe and reasonable speeds, regardless of posted speed limits. The faster group of drivers, still driving at reasonable speeds (i.e. the 85th to 90th percentile), will experience the fewest accidents per mile driven. Those drivers traveling significantly slower or significantly faster than the 85th percentile group experience far more accidents. ))
If Mr Baxter considers traffic at the 90th percentile to be the limit of safe drivers who will experience the least number of crashes per mile driven why does Mr Walker insist on allowing upto the 95th percentile? which is filling our heads with bad information?
Incidentally the point at which I have chosen to post and enforce is largely supported by Mr Baxter's comments here. The 90th percentile is about 2.5mph above the 85th percentile speed. If You calculate an 85th percentile speed , round it down to the next 5mph increment and then allow 5mph of grace and enforce starting at the 6th mph, you will enforce at between 2 an 5mph above the 85th percentile speed…..cont….
Mr. Mckrackin is in error here. The 90th is usually only 1 mph above the 85th, not 2.5 mph above it. It does represent a point where the risk curve is rising in most cases, but still rising very slowly and the 90th will be below the risk level of the median speed (or about the middle of the pace) — and WELL below the risk level for the bottom of the pace.
The 90th percentile is the point that Mr Baxter has indicated that driver's will begin to experience far mor accidents. If that is not true then why is an NMA member telling us that? If it is true then why do you insist that speeds higher than that should be allowed absent enforcement actions, even though unlawful. Obviously you aren't looking at the same crsah incidence curve that the rest of us are looking at.. My methodology accounts for enforcement against unlawful behavior that is, as Mr Baxter indicates, adding risk of far more crashes. Either Mr Walker is lying to us or Mr Baxter has lied to us, both cannot be truthful with what they had asserted.
Mr. Mckrackin has grossly misquoted Mr. Baxter. Jim Baxter said
"The faster group of drivers, still driving at reasonable speeds (i.e. the 85th to 90th percentile), will experience the fewest accidents per mile driven. Those drivers traveling significantly slower or significantly faster than the 85th percentile group experience far more accidents."
Since the 90th is normally 1 – that is ONE – mph faster than the 85th, I find it impossible to believe that anyone would consider someone in the few mph above the 85th/90th percentile to be "significantly faster"
Mr. Baxter told no lies, nor did I. Mr. Mckrackin tries to twist words to make the difference of the next 1 to 4 mph look like the difference between very safe and totally crazy or about to kill someone with no control of the car — and nothing could be further from the truth in traffic safety engineering.
Mr Baxter uses the term significantly in a very ambiguos way. Does he mean significantly faster or does he mean significantly higher in the speed distribution? Mr Walker and the NMA have a terroristic approach to traffic engineering. If you don't support their views you are the enemy and they need to smear you and discredit your opinions no matter how close they are. Mr Walker and the NMA have both stated that they would like to cause a collapse of our traffic justice system and they have both offered suggestions on how that can be accomplished. What would a collapse of our traffic justice system cause as far as traffic safety?
"Significantly slower or faster than the 85th percentile group" is extremely clear, only Mr. Mckrackin could tortuously read this to mean that 2 mph faster than the 85th or 90th put you in the crazy group.
We are done, Mr. Mckrackin, you not only don't get it, you don't WANT to get it.
PS: Michigan operates with the methodology I promote (wherever not blocked from doing so by arbitrary statutory limits). The state police officers responsible for most of the realistic speed limit changes have received two major Governor's Traffic Safety Advisory Commission awards for their work to improve safety with realistic speed limits. If Mr. Mckrackin chooses to rant and call this a terroristic approach to traffic engineering, he is only displaying his own ignorance. Note that our fatality rate is well below the national average.
If he wishes to claim our traffic justice system has collapsed or will collapse for enforcement on MI roads with proper 85th speed limits, he has his first amendment rights to say any crazy things he wants – but it is another baseless rant founded upon nothing.
Note, the fatality rate being below the natioonal average is not a byproduct of the speed limits. In My home state which, has lower fatality rates than the national average and those experienced by By Michigan(all the way back to 1994) yet does not have the same liberal view of allowing speeds in excess of the 85th as Mr Walker or his home state of Michigan. In fact My Home state, according to Mr Walker, is one that does not set it's speed limits with safety in mind.
I have read the posts by Mr Walker and other members of the NMA about how they could cause such a collapse. I have made no assertions as to the method s that Michigan employs being such a method. Now Mr walker is just trying to put words in my mouth.
If you use Mr Walker's methodology you will post the 85th rounded to the nearest 5mph increment and then allow 4mph and enforce starting at the 5th mph. 60% of the time you will achieve exactly the same posting as I do but enforce 1mph sooner. the remaining 40% of the time Mr walkers methodology would enforce at 6 and 7mph above the 85th. According to what Mr Baxter tells us, driver's traveling at 6 or 7 mph above the 85th will experience far more accidents. The science, of Physics, tells us that these crashes will also be exponentially more severe that those of vehicles traveling at slower speeds. for speeds in excess of 37mph for every 3 mph your speed increases your risk of injury and/or fatality doubles…..cont….
Correctly rounding up or down from either the 85th or the top of the pace will give varying amounts of grace – assuming you enforce at +5 over the number on the sign. Mr. Mckrackin's mixed method of rounding by comparing the 85th and the top of the pace appears nowhere in the literature. If he would like to find a benefactor for a large grant, partner with a known and unbiased researchers, find perhaps 40 or 50 places to correct the speed limits, do half with his method and half with just using the 85th per the literature — then we would have some basis of comparison.
Until I see something like that, I prefer to just use the 85th and not have to spend perhaps another decade educating people who already understand the 85th what the Pace means and how it could be used with a more complicated method to set limits.
Mr Walker's method also does not appear in literature regarding how interstate speed limits should be set. I have merely taken what Mr Walker has told us that corrected speed limits should accomplish and derrived a method of posting and enforcing them that actually accomplishes what it should. ALL major unbiased researchers and traffic engineers know that the 85th and the pace are relavant parameters that need to be examined. That mr Walker arbitrarily wants to disregard the parameter of the pace so he can accomplish higher numbers on the sign are evidence of his goals and the goals he works to accomplish for the NMA.
Mr. Mckrackin is in error in the first sentence. Parker said he would like more data on freeways, but saw no reason the principles did not apply. Cirillo found the sweet spot of the lowest freeway crash risks were 11-16 mph over the median or average speeds – that puts them in the low to mid and even high 80 mph range.
YES, you should look at the pace, but you will find it +/- 1 mph in 90+% of the cases and within +/- 2 mph in another 8% of the cases. I only found one case where the pace was 3 mph different in 118 cases. Mr. Mckrackin wants us to believe that there are big differences in what happens using the pace instead of or along with the 85th and that is just nonsense. In 90% of the cases, the posted limit is the same. In 4% it is higher using the pace, in 6% it is higher using the 85th. It would be very hard to think of two data parameters that were more alike. They ARE alike because they basically measure the same behavior from the same data sets and for all practical purposes the 85th = the top of the pace within a margin too narrow to make any difference.
I choose not to lose another decade reeducating the public and the politicians for something that does not matter.
NOTE in the cases where the Pace led to the higher limit, several of them were on city streets where the higher limit would cause more concern among ignorant citizens and politicians. All the ones in the 118 cases I looked at where the 85th gave the higher limit were on freeways or rural highways where the higher limit would cause far less concern for most people.
If I did get a grant and perform the experimental postings and submitted a paper with resluts not favoring Mr Walker's goals or the goals of the NMA my paper and my work would be added to their long list of biased researchers to not consider when posting the speed limits. Mr Walker's and the NMA's goals are painfully obvious and seemingly not in the best interest of safety.
I admit I would look at the data VERY hard if it had Mr. Mckrackin's name on it. But, if the research partner he chose to do the work was a recognized and unbiased expert and the data clearly showed fewer accidents with his method, I would consider supporting it.
If A speed limit was set at 65mph as a corrected 85th percentile speed limit and you knew that you could drive at upto 75mph without being ticketed how fast would you drive?[polldaddy 2739863 http://answers.polldaddy.com/poll/2739863/ polldaddy][polldaddy 2739863 http://answers.polldaddy.com/poll/2739863/ polldaddy]
The poll does not contain a key potential answer.
X I would drive around 65 mph, and perhaps up to about 69 mph if the conditions were good – knowing that the next 1-4 mph above the posted limit are very safe and that the probability of enforcement in that range would be nil. This keeps me out of the top few percent where the risks for speed-alone dangers rise significantly, along with the probability of legitimate safety-based enforcement.
In the 4 poll answers shown
The percentage in the first group 75+ will be very tiny, less than 2%, and they should definitely be targeted for enforcement.
The second group, 65 or below, will have about 85% of the traffic.
The third group at or just under 75 (say 71-75) will be small – maybe 2% to 4% and they should be targeted for enforcement.
The fourth group will have roughly 8% to 10% of the total and they should be left alone, because their risk factors are very little above the people at 61-65 mph (top half of the pace ending at the 85th).
So rewrite the poll! Likely there will be no activity on it because there is no one else posting here
If a speed limit was posted at 65mph as a corrected 85th percentile speed limit and you knew that you would not be cited unless you exceeded 75mph how fast would you drive? Please answer the poll[polldaddy 2739826 http://answers.polldaddy.com/poll/2739826/ polldaddy]
If a speed limit is set at the 50th percentile but not enforced untile the 85th percentile what safety gain is achieved by reposting the speed limit to the 85th and enforcing at the 95th percentile? Mr Walker would like you to believe that simply setting the limit at the 85th is all that is neeeded to create safety. It is not! There is an amount of compliance that is associated with increasing the limit to the 85th however if you then enforce at a higher speed than the 85th you allow non compliance without punishing the behavior. You cannot stop a behavior without punishing those who exhibit it. If we do as Mr Walker suggests and don't enforce against any of the drivers who exhibit behavior that violates the corrected speed limit upto the 95th percentile speed and beyond then the new speed limit is effectively the 95th percentile or above. That is unacceptable.
http://www2.wjbf.com/jbf/news/state_regional/sout...
Of course everybody knows that speeding enforcement is never about revenue, always about safety. RIGHT. NOT.
Is every venue this voracious and corrupt? No, of course not.
But are there enough of them around the country (like Ann Arbor and Ohio among others) to destroy the assumption people should be able to have that speeding tickets are about safety and not revenue? Yes, most definitely, and especially when you see that the posted limits in so many places define 50% or 70% or 90% of all drivers as violators. This sort of predatory revenue based use of speeding as a cash cow using artificially low limits will not be really solved until most main roads are posted with the correctly rounded 85th limits.
The small number of legitimate exceptions to post below the 85th on main roads then need to be fully documented by the engineers (and police in some venues) on the paperwork, called a Traffic Control Order in Michigan, to show WHY the road was posted lower for truly hidden hazards that are not apparent to the average driver, difficult-or-impossible-to-fix engineering defects that cause the area have a high crash rate, etc.
When most main road posted speed limits again respect the science and the super-majority (85%) of safe, sane, sober, competent drivers —- then those drivers will again respect traffic laws in general and the officers that enforce them. Not unless, and not until.
Will there always be a few crazies and high flyers that are way above the normal speed distribution and whose speed can cause safety problems? Sure, and that is where the speed-alone (with no other driving errors) enforcement needs to be exclusively focused — IF safety is the true goal for posted speed limits and their enforcement.
I have never claimed that enforcement for revenue doesn't happen. However, I have said that Mr Walker, Mr Young and the NMA always overstate how often it happens. Why, Because the NMA is a "for profit organization" that makes money when you are unhappy with the government and how they are setting the speed limits. I would bet that both Mr Walker and Mr Young are officers in the corporationa nd recieve some sort of compensation from the organization. Funny thing about MOST of the venues that Mr Walker cites as corrupt and enforcing speed limits in a manner that generates revenue. They can easily be defeated, all one has to do to defeat such a venue is obey the speed limits. If you obey the speed limit they can't ticket you for speeding and they can't get any revenue from you……cont…..
It is not hard for enforcement to be for revenue when the average highway posted limit is around the 30th percentile speed. Add a 10 mph grace and you can ticket a LOT of vehicles at or very close to the 85th percentile speeds, the ones least likely to crash. Mr. Mckrackin refuses to believe the average low percentile level that posted limits represent, at least in the eastern part of the country.
He knows that I am a volunteer for the NMA, have never been an officer, and the only money I ever got from the NMA was a grant from the Foundation to win my two court trials. I recently received some rough numbers on the finances of the NMA and would never publish them – they are too small. If Mr. Mckrackin believes that anyone makes much money from working for the NMA, he is profoundly mistaken.
Everyone knows that revenue based ticketing can be defeated by driving at what was about the 20th or 30th percentile speed, roughly at the bottom of the natural pace speed range. This will occur at about the time Hades generates mile deep glaciers, a fact that Mr. Mckrackin well knows, but he keeps bringing up the "Impossible Dream" of compliance with grossly under posted limits. I prefer to support practical solutions that can actually work to improve safety and smooth traffic flow, not theoretical ones that will never come about.
The point Mr Walker fails to prove is that the speed limits were set purposefully at the 30th percentile specifically to generate revenue. I don't believe the "AVERAGE" speed limit is posted around the 30th percentile but for argument sake I will accept that figure. Were those speed limits set specifically to generate revenue or were they properly set and then disregarded largely because there was a huge enforcement grace allowed above them? That I have drawn different conclusions about this subject matter than Mr Walker, Mr Young or the NMA, does not negate my acceptance or consideration of any facts. This is a smear tactic that many NMA members use in these type forums to bully opposing opinions into not commenting further……cont…..
Limits set around the 30th percentile may be: A. deliberately set for revenue purposes, B. uncorrected limits left over from the NMSL, C. under posted out of gross ignorance by politicians, D. set in response to complaints from uninformed citizens who do not realize it makes things worse, or E any number of other reasons. Enforcement of those limits in most cases produces only more revenue, not safety enhancements – regardless of whether revenue was the corrupt goal, or not. The grace allowances in most places are NOT great enough to avoid ticketing our safest drivers at or near the 85th. The RESULT is unacceptable, regardless of the reasons it occurs.
Whatever the reasons, grossly under posted limits are wrong. They tend to raise the accident rate, increase conflicts between vehicles, increase the speed variance, promote aggressive driving, and destroy the credibility and respect for speed limits, traffic laws in general, and the officers who enforce them — all unacceptable results. All but the small percentage of legitimate special cases on our main roads and highways need to be corrected to the correctly rounded 85th percentile speed.
There are no smear tactics involved, only facts and proven scientific principles.
Reply: Mr. Walker forgets that speed limits can become obsolete through non compliance even if they were set properly. Mr. Walker and the NMA blame the government for the short fallings of the public. Notice how he calls any of you who believe that 30mph through your neighborhood a protection of your children uninformed or ignorant.
Another point Mr. Walker refuses to accept is that we can’t simply define what is lawful by redefining unlawful behavior as lawful. He refuses to consider that when you allow a behavior that is unwanted (in this case speeding) to exist without punishment more drivers will begin to exhibit that behavior. At some point the number of non compliant drivers out numbers the compliant drivers. Under posted speed limits ONLY raise the accident rate, increase conflicts between vehicles, increase speed variables promote aggressive driving, and destroy the credibility for the limits, traffic laws in general and the officers who enforce them through non compliance. If we all complied with the speed limits set by the government, the accident rate decreases, conflicts between vehicles decreases, speed variations decrease, aggressive driving is only engaged in by unlawfully proceeding drivers. …cont…
Since there is no creep on almost all surface roads, corrected limits do NOT become obsolete over time – this is simply a false claim by Mr. Mckrackin. Rural freeways creep at about +5 mph per 10 to 20 years, a very slow progression fully in line with the safety improvements in cars and roads.
Mr. Mckrackin refuses to accept that artificially low speed limits do not, and will never, affect actual travel speeds by more than about 3 mph on surface roads and perhaps 4 or 5 mph on freeways. His argument about non-compliance growing with observations of other drivers is simply not true.
Absolutely correct that high compliance with low limits would change all the equations – but it is totally useless to spend time on a theoretical that is never going to happen. Why Mr. Mckrackin wastes time on this is a mystery. Essentially every engineer and any police officer with much experience knows these facts.
There is no reasoning with your circular argument.
What, pray tell, is circular about the fact there is no speed creep on most surface roads after their limits are corrected? This is factual, and there is a mountain of data to prove it. See Parker, among others.
What, pray tell, is circular about the fact that rural freeways have a slow speed creep of about +5 mph for every 10 to 20 years of time? There is a lot of data to show this.
What, pray tell, is circular about the fact that posted limits way below the safe and comfortable travel speeds for most people do NOT reduce the speed distribution by more than trivial amounts? There is a mountain of data to show this.
IF safety and smooth traffic flow are the true goals, then you must START from the facts, not the nice sounding theories that don't work.
There is no reasoning with your circular argument. It is obvious that you know nothing of human Psychology or behavior modification. If you allow a speed a large portion of the speed distribution will travel at that speed, A portion of the speed distribution expects that the limits will be posted with a margin of error so that exceeding it is not unnecessarily dangerous. This is the 15% above the 85th percentile. If you then allow speeds upto the 95th percentile those 15% will drive at those speeds. As soon as the remaining speed distribution sees that there is no retribution for breaking the law and that it is actually encouraged they too will speed up regardless if it is a surface roadway or interstate. Prime example of this is the roadway you were ticketed on. The speed limit was set with the two schools in mind at 30mph. however enforcement didn't take place until 10mph later. what happened? the 85th percentile moved to near the enforcement speed even though there were two schools present and speeds should have been reduced accordingly for them. …cont…
The third sentence above – "If you allow a speed a large portion of the speed distribution will travel at that speed" – is simply false. Enforcement has only a very small effect on the speed distribution EXCEPT when the posted limit is way below reality and the size of the ticket gets important. People drive at the speeds they find to be safe and comfortable for themselves and changing the posted speed limit changes the actual 85th by a MAXIMUM of 3 mph on surface roads, with a usual change of less than 1 mph. Mr. Mckrackin's beliefs (or statements) that significant portions of the speed distribution change speeds based on enforcement is simply false – it doesn't happen.
If this did happen on a road with (example) an 85th of exactly 40 and a typical area grace of 9 mph where ticketing begins at +10, then you would see 85% at 40 or below, very few vehicles at 41 to 46 or so, and a big cluster at 47 to 49. That distribution does NOT happen. Mr. Mckrackin states fears of results that simply do not occur, so engineers do not take those false fears into account.
The speed limit on Nixon Road was politically set by the city administrator at a level 5 mph below what even the engineer wanted or the school superintendent said was OK. The limit was set artificially low in anticipation of heavy citizen opposition to setting the proper and safest limit, opposition from citizens who generally have no clue how traffic safety engineering actually works. The 85th at the time was 40 mph when the road was posted at 25 mph. Posted at 30, 27 years later, the road still has an 85th of 40. There was no change in the 85th and Mr. Mckrackin's statement that the speed distribution moved is patently false. There is a procedure in MI law to identify school zones with signage – this area is NOT marked. There is a procedure to have reduced speeds in school zones during the hours kids might be present – this area is NOT so marked.
Along comes an NMA member who has an anti government agenda who decides to test the posted limit without regard for the children that may be present. The NMA finances his civil disobedience. This is a testiment of just how far the NMA will go to raise every speed limit in America regardless of how it effects safety.
Nonsense., and Mr. Mckrackin't post just above is just garbage.
The NMA financed my appeal to defeat a posted speed limit set in violation of state law. Remember, the area has two schools, one large public one and one tiny private one, right next to each other. The city does not even mark the road as a school zone. A visitor to the area would have NO clue that there were schools there. I was not "testing" the posted limit, I was just driving at the 85th because that is safe and comfortable for me. The ticket was in the early evening, not during school hours. The only reason I got the ticket in the first place was my detector was out of calibration. In hindsight, that was very fortunate and I made a very good test case to defeat Ann Arbor's illegal speed limit there. I understand the issues, I helped get PA85 passed to support the state police, and I was able to fund the fight with some of my money and a grant from the NMA.
The NMA fights, and will continue to fight for the RIGHT posted speed limits — usually the 85th – because that promotes three results. 1)The lowest crash rate, 2)the smoothest traffic flow with the fewest conflicts, and 3)the end of predatory ticketing of safe drivers at or near the 85th. Note that we are winning this fight.
It is the non compliant drivers that cause all the problems Mr. Walker listed regardless of where the speed limit is set or how correct it is. So if all of these things are unacceptable results and they are caused by non compliance why isn’t Mr. Walker or the NMA promoting compliance? Mr. Walker’s proposed methodology of how to set and enforce limits promotes non compliance. The only difference between his proposed system and the system we have today is the numbers on the signs. One must consider is that by design to ensure even higher speed limits in years to come.
Trying to promote the impossible is an absolutely useless exercise. I and the NMA are ONLY interested in practical solutions that can work.
The NMA is only interested in higher speed limits, regardless of how they effect safety
The NMA is only interested in the RIGHT speed limits that improve both safety and smooth traffic flow – usually the correctly rounded 85th.
No one who truly understand the principles behind 85th percentile speed limits would ever try to promote compliance with artificially low limits. Such efforts are a total waste of time AND tend to make things more dangerous in the process.
Mr. Mckrackin states falsely "Mr. Walker’s proposed methodology of how to set and enforce limits promotes non compliance." Proper 85th limits promote compliance, by definition, of 85% of the traffic flow. This is a massive improvement over today's compliance rates of 50% or 30% or 10%, depending on how terrible the limits are in the area. The next 5 mph interval of people who are almost in compliance and very close to as safe as those right at the 85th will tend to have about 10% of the vehicles. Then you focus enforcement versus the (average) top 5% and you have a small enough pool to have an effect over time.
I know what Mr Walker has said to me in conversations here and in private Email. I have no basis of comparing the truthfulness of said comments. Given the propensity of NMA members to lie I see no evidence that suggests that I should accept his statements as truthful. The NMA financed a rather large defense for Mr Walker so he could get away with speeding on a roadway that contained 2 schools. The NMA is a "for profit organization" If Mr Walker would like us to believe that even the officers of this organization do not profit from it then he would need to supply the organizations tax records. Then again If we consider the blatent dishonesty of this organization they probably lie about their taxes anyway……cont…..
The NMA helped to finance, along with substantial amounts of my money, a defense of a speeding ticket where the posted limit violated state law. Two judges agreed and dismissed the ticket. If Mr. Mckrackin truly supports allowing cities to post limits in direct violation of their state laws, then we have rather different value systems. Note that the ticket was in the early evening, not during school hours and I have repeatedly said I would support having that area posted at 40 to match the 85th percentile, with special 30 postings per state law for the hours children are likely to be present. The City of Ann Arbor does not even identify the road as a school zone in any way.
I choose not to publish the limited financial data I received recently, the totals are too small. Note that part of the NMA is a normal corporation, part is a 501(c)3 non profit organization. in any case, given Mr. Mckrackin's propensity for unfounded personal attacks, I see no reason to reveal the data to him.
Mr. Walker does not wish to reveal the numbers because they support my assertion. Any court battle that was taken to the extent that Mr. Walker and the NMA took this fight is costly. I am not “attacking” anyone. I am simply telling the readers they should follow the money trail to look for motivations.
Mr. Walker was well aware that there were 2 schools on that roadway before he received his citation. Was Mr. Walker absolutely certain that there was not a school function going on when he proceeded down this roadway at an unlawful speed of????(What was your speed?). I find it Ironic that you are criticizing the city for not obeying State law when you yourself thumb your nose at the law every time you choose a speed above a posted limit. I applaud the city’s civil disobedience of State Laws they disagree with. I hope it is VERY costly to whomever takes them to court to force them to comply just as it was costly for the city to try to enforce the law against Mr. Walker.
No, Mr. Mckrackin, the numbers do not support your foolish accusations. We DO have a fund to support legitimate challenges to corrupt systems and I was granted some of that fund to win my case.
Michigan law does NOT allow reduced speeds in a school zone in the evening, only during morning and afternoon times when kids may be present, and at lunchtime IF the kids are allowed to leave.
My ticket was 40 in a 30 and the 85th has been 39-41 mph for at least 27 years, while the road has been posted at either 25 or 30 mph.
I know of several more cases where people used the same arguments I did versus Ann Arbor posted limits and the tickets were dismissed without any need for an attorney.
If Mr. Mckrackin truly applauds cities that defy state law, then we have some different value systems.
If everyone knows that revenue based ticketing can be defeated by driving at what was/is the20th or 30th percentile speed(which I doubt the existance of as many places as Mr Walker suggests) Then why do they NOT take that action to fight against revenue based ticketing. It is NOT the "impossible dream" that I am bringing up. I bring up compliance because Mr Walker and the NMA refuse to address compliance beyond the statistical statement that it will increase with increased speed limits. What he fails to explain is that as long as there is a difference between the posted limit and the enforced limit compliance will decrease. He fully knows this and it is why he insists that after the speed limits are corrected that enforcement NOT take place against 2/3 of the drivers who will choose unlawful speeds. That in itself is a non practical solution designed to increase travel speeds, 85ths and speed limits. thereby ensuring that the NMA is needed and that the officers of that organization continue to profit from it's revenue.
People do not, and will not, drive at speeds far below the range they find safe and comfortable. This has been known for at least 70 years. Time has a value. Mr. Mckrackin't statement above "What he fails to explain is that as long as there is a difference between the posted limit and the enforced limit compliance will decrease." is simply false. Correctly rounded 85th limits get very high compliance by definition and the speed distributions do NOT then tend to increase (except perhaps for a one time correction for limits that were posted more than 10 mph below the correct point – particularly on freeways). There is no creep on surface roads, rural highways operate today within about 5 mph of the speeds they did 70 years ago. We have reams of data showing no speed increases on city streets and arterials with corrected limits – a MAX change of 3 mph, and usually less than 1 mph. Rural freeway speeds rise about 5 mph for each 10 to 20 years – a progression fully in keeping with safety improvements in cars and roads. Mr. Mckrackin's views of what will happen with corrected 85th limits are simply wrong.
One could argue, I guess, that they could be targeted by a corrupt venue and be cited to generate revenue even if they complied. however if that is the case in any particular venue they have greater problems than where the limits are set. If a venue is as corrupt as Mr Walker implies, to engage in revenue gathering practices, having corrected speed limits is not a guaranteed safeguard against the corruption.
There have been a few such venues, New Rome, Ohio was a particularly infamous one This was a place where tourists were often guilty until proven guilty – they would find SOMETHING wrong with any car or any driver for revenue purposes. It got so bad the state and county dissolved their legal entity as a city.
But, in almost every case, correctly rounded 85th limits will fix the problem. Virtually no venue will ticket for less than 5 over, and that puts the enforcement versus the average of the top 5% where it belongs —- IF safety and smooth traffic flow are the real goals.
Do I believe that speed limits should be set using a standard of practices? yes
Do I believe they should be set using science and in order to provide the best safety benefits as possible? yes
However, I also believe that the venue is the authority that decides what the speed limt should be. If they tell you that it is unlawful for you to travel at speeds greater than xxmph, you are breaking the law if you exceed that xxmph and deserve to be cited and sanctioned.
Mr. Mckrackin and I and a great many other people who have studied this issue have agreed that a scientific set of mandatory practices for setting limits nationwide on the basis of standard engineering practices designed for safety would be a BIG step forward. The MUTCD was intended to do this and the most important word in the acronym is UNIFORM. But, the MUTCD has been watered down so severely that arbitrary practices are the norm, not scientific or safety based ones.
How is a driver from the Carolinas supposed to deal with an urban freeway in Michigan posted at 70 and that number is pretty close to the 85th percentile — and then go into an identical or even safer style freeway in Chicago posted at 55? Why should rural two lane highways be posted at 55 in so many states (left over from the NMSL era and never corrected back up from the roughly 30th percentile level) and then see identical style ones in Texas posted at up to 70 mph to match the normal speed distribution? Why can you go west on I-80 and see posted limits anywhere from 55 to 75 mph on road segments that are essentially the same in design and safety features? It is wrong. We do NOT have anything like uniform rules and posted limits in the USA and it would be a huge step forward to get them.
We all understand Mr. Mckrackin's support in principle for drivers complying with any posted limit, but it is totally unrealistic IF the limits are totally unrealistic on the low side. We have 30+ years of data to show it will never happen and for venues to use that known fact to under post their best roads with less safe artificially low limits to facilitate predatory ticketing for revenue is corrupt and immoral in the extreme.
Unfortunately Mr. McKrackin believes that the scientific principles that should be used in guiding the setting of speed limits should not be limited to those principles that support raising the limits. I have mentioned a few ideas to Mr. Walker on how there could be a compromise between the highest possible limits that the NMA is demanding and the under posted limits we experience today. Unfortunately Mr. Walker thinks that any idea that isn’t his is not practical and any plan that actually enforces against unlawful behavior is unacceptable. Mr. Walker tells us “the basis of standard engineering practices designed for safety would be a BIG step forward.” He also has told us that the safest point of the risk curve is at or near the 85th percentile (I believe it to be below the 85th percentile). Does his plan to allow speeds in excess of the 85th percentile speed and up to the 99th percentile speed to not be enforced against in alignment with “standard engineering practices designed for safety”? ….cont….
85th percentile posted limits are the best-practice in almost all cases, and arbitrary changes to that number are not justified in most cases. Today, that means most limits go up because most limits are posted too low. My support for 85th limits is NOT my idea, it the overwhelming choice of unbiased researchers for the last 70 years.
I have never seen a researcher say to post the 85th and then allow zero grace. I have never seen a researcher say to post the 85th minus 5 mph, so that enforcement begins right at the 85th. i have never seen a researcher say to always round down. So, yes, the method I support IS in alignment with the body of research dating back 70 years now.
What is the need for rural two lane highways being posted at speeds greater than 55-60mph? Do we really need to get to the local store that quickly? Do we need to have triple digit speed limits on roads that have residential property adjoining them? The problem with rural two lane highways is that they are not limited access and are open to pedestrian, bicycle, child and pet traffic. How fast is fast enough on those types of roadways? Mr. Walker is trying to define that all roadways be set by the standards of the sight distances and driving environment of a particular state. Should the roadways in Texas be set according to the sight distances and stopping distances of highways in the Rocky Mountain States? No, so why should the reverse be a practical suggestion? I firmly support a more national uniformed system of traffic control but see many limitations if we are to be bombarded with ridiculous suggestions such as NY should be posted just like Texas. Unfortunately Mr. Walker is too small minded to want anything other than simply the fastest speed limits of one particular state to become the standard for all states….cont…
Maybe Mr. Mckrackin has very little experience on two lane roads where the nearest real grocery store is 20 or 30 or 50 miles away on a road with an 85th percentile speed of 65 or 70 mph. I do, and so do millions of people in the western states. Plus, if the road is safe and comfortable for the average driver at 65-70 mph, then painting lower numbers on the signs is both useless and counter to safety. Why Mr. Mckrackin supports this anti-safety measure is a mystery.
The right speed limit is almost always the 85th, individually measured and posted. I do not support most blanket limits – they post some roads too high and others too low. It happens to be the case that many two lane rural highways have an 85th around 65 mph, whether located in NY or MI or MO or NE. This may well be because the design criteria are similar.
Arbitrary reductions in posted limits for visible pedestrians, bikes, etc. are not acceptable, because they do NOT change the higher speeds – they just mess up the distribution and spread the variance and increase conflicts. Why Mr. Mckrackin supports these anti-safety results is a mystery.
No, Mr. Mckrackin, I support the RIGHT posted limits – usually the 85th, and NOT whatever is right in state one to be the number for state two, unless the 85ths come out the same.
Maybe Mr Walker should consider that NOT every State is Michigan and corrupt and not every State is Texas where there is nothing alongside the two lane roadways. If he did He may not draw the faulty conclusion that ALL Two lane rural highways need to be posted at 80-100mph.
He should also consider that just because the nearest store is 20,30 or 50 miles away doesn't equal there is NOTHING in between his home and that store. Even Germany, where the infamous Autobahn exists with it's unrestricted speed limits, surface roadways are limited by reasonable speed limits. I get raising the speed limits on rural interstates and limited access roadways and traffic that is too slow to be in the pace can use other roadways instead. Now Mr walker would increase the speed limit on those roadways increasing the speed differentials of traffic on the most dangerous roadways that have fatality rates 2 to 4 times that of the interstates. Where does it end? .,..cont…
Mr. Mckrackin's first paragraph above about my wanting all 2 lane roads to be posted at 80-100 mph is nonsense, and even he knows that. It is just an unsubstantiated rant.
True, NOT every state is Michigan, very few eastern half states are working as hard as Michigan to get posted speed limits set at the safest 85th levels. True, NOT every state is Texas, but many states have very quiet rural highways with very little development. On M-28 in the Upper Peninsula there is a section called "The Seney Stretch" between the towns of Seney and Shingleton that is die straight for over 20 miles. If you had a tall tower on one end, you could look straight down the road to the other end. It is bounded mostly by forests and has VERY few access points. It is posted at 55, which is nuts. That will get fixed some day, but other roads in the lower peninsula will get precedence first.
Mr. Mckrackin apparently refuses to recognize that IF the 85th is 65 or 70 on a good rural highway, then that is the safest place to post the limit. If you leave the good surface roads like that posted at 55, which IS the normal practice in so many states, then THAT is what spreads the speed distribution and causes more conflicts between vehicles. A small percentage will obey a 55 limit which will be at or below the bottom of the pace, but most will not – so the speed distribution is spread and conflicts increase. This idiotic situation will end when most main road limits are posted at the safety-optimum point, usually the 85th.
Now, I agree on one point with Mr. Mckrackin that he implies above. It would be better to fix the limits on rural Interstates and limited access roads first, and then fix limits on the rural surface roads. However, that runs into statutory limits set by unqualified politicians that are very difficult to get changed. We have to make progress wherever not blocked by state laws, even if the order of the changes is not optimum.
In Mr wWalker's world Grandma can no longer travel on the interstates or other limited access roadways because she doesn't want to travel at 85+mph. So grandma stays on the more dangerous roadways and increases her risk of crash, injury and fatality 2 to 4 times just so she can visit her grand kids. Then Mr Walker increases the speed limits on those roadways to 70mph so that Grandma is uncomfortable driving anywhere…cont…
Mr. Mckrackin's statement about Grandma above being forced off the Interstates is foolish nonsense.
On an Interstate with a posted limit of 75, 80, or 85 mph to match the real 85ths around the country, there is plenty of room for Grandma to be safely at 60 or 65 mph where she finds it safe and comfortable for herself. With the limit posted correctly, lane courtesy tends to be a LOT better, most people will keep right except to pass (as is the law in many states and was once taught in driver's training), and the flow is very smooth. This is the "secret", of course, to most European freeways which accommodate large speed differentials quite safely.
I grew up driving in MI and IN where the posted limits on rural surface highways were 65 mph. It worked well and those limits would largely apply today if they were set with 85th methodology. SOME western state rural highways and some VERY rural areas of eastern states will survey for 70 on surface highways and those should be posted that way. People who have driven roads like that know that part of the reason for the higher 85ths are the low traffic counts, the low access point counts, and the availability of decent passing zones to get by Grandma who wants to drive at 55 or 60 because that is where she finds it safe and comfortable for herself.
Just because the surveyed 85th is X mph, does NOT mean everyone drives at that speed, or even that very many do. People right at the 85th speed are a very small percentage of the total, most are below.
Mr Walker and every other NMA I have discussed this issue with all said at the begining of our conversation "All we really want is reasonable speed limits". That implies they want reasonable speed limits for everyone. In reality they just want higher speed limits so that they can drive at faster speeds lawfully whether to save time or for the thrill. If Mr walker really wants these unreasonable speed limits that will effectively legislate grandma off the roadway then he should first make other forms of travel available to her.
The above is just nonsense. Reasonable speed limits by almost every unbiased researcher over the last 70 years ARE 85th limits and they do NOT drive Grandma off the roadways. That is just nonsense.
Obviously Mr. Walker has an incorrect understanding of my support in principle of drivers complying with posted speed limits, because he has once again misattributed my position. My position is NOT how can we obtain compliance with under posted limits, it is how can we insure compliance with corrected limits (so we don’t repeat that 30+ year history). Mr. Walker tries to imply that because I am concerned about compliance I must want lower limits. Why would Mr. Walker keep incorrectly implying that this is my position after we have talked in private Email for over a year and I have made it clear to him on several occasions that this implication was incorrect?
Corrected limits DO get compliance, a fact that Mr. Mckrackin refuses to realize. Surface roads have no creep in most cases. Rural freeways may need to resurveyed after 6 months to a year and reset again — IF the posted limit was way below reality. Then it will be stable except for the +5 creep every 10 to 20 years. Mr. Mckrackin either does not accept this, or believe that slow creep is unacceptable. If he thinks that slow creep is unacceptable, then we simply disagree.
That the speed limit on the sign defines 50%, 70% or even 90% of the drivers as violators is meaningless given that almost all speed limits are enforced with a grace. Typically the enforced speed is near the 85th percentile and in a small number of exceptions below the 67th percentile speed.(Midway between the 85th percentile and the median speed) Ironically Mr Walker says that this system has failed miserably but then advocates using a system that does exactly the same thing, post at the 85th percentile and enforce as high as the 98th percentile or higher in some cases.
Mr. Mckrackin and I differ greatly on this point. When the posted limit defines 50% to 90% of all drivers as violators, there is zero chance for respect for posted limits and the officers that enforce them, and to some extent respect for any traffic laws. The grace is NOT posted on the signs and can vary a great deal even in one area, so any one driver never knows if their wallet will be the target that day. Having ANY drivers cited for speed-alone when they are at or below the 85th is essentially criminal in my view. It is basically government sanctioned stealing from the safest drivers on the road. Posting the 85th and using a 4 grace will put the enforcement versus an average of the top 5%, right where it belongs IF safety and smooth traffic flow are the real goals.
Mr. Walker implies here that the law was made to define 50-90% of the drivers as violators, that is NOT the case in a majority of the cases that suffer from speed limits posted below the 85th percentile speed. The reason that so many motorists don’t respect the speed limits is because of the way that they are enforced. The number on the sign says 55mph and 65-72mph is allowed before any enforcement action is taken. Of course as more drivers discover that they will not suffer enforcement actions at speeds above 55mph they begin to choose speeds above 55mph. Mr. Walker has implied in the past that increasing the limits is not meant to increase travel speeds. In the article above he tells us that travel speeds will NOT increase. The only way for that to be true in my example here is if enforcement action continued to exist at 72mph regardless of where the 85th is. Mr. Walker would have us post 70mph and enforce at 75mph which would then alter the dynamics of the speed distribution and encourage drivers to increase their speed….cont…
This argument of Mr. Mckrackin's is simply not true. Enforcement has only a very minor effect on speeds – with any level of enforcement most venues can afford. Speeds chosen are those most drivers find safe and comfortable and if we post the 85th, the speed distributions remain remarkably stable. Mr. Mckrackin's fears simply do not happen.
Mr. Walker keeps throwing this line at you “IF safety and smooth traffic flow are the real goals.” Let’s apply that to what he has told us in the article above. 1) above he tells us that travel speeds will not increase, he has even gone to great lengths to provide us with empirical evidence of that in his charts. Has the smoothness of traffic flow really changed if the speeds have not changed? Has the traffic magically gotten safer if the speeds haven’t changed? If the travel speeds have not changed, then the position along the risk curve has not changed. If the position along the risk curve has not moved safety has not increased….cont…
The speed distribution tightens a bit, the biggest safety improvement comes from moving some of the slowest cars UP into or closer to the pace. This reduces conflicts, passing, and the risks of aggressive driving. The top end changes very little. Mr. Mckrackin's last sentence above is false, you get more safety by reducing conflicts.
I agree that when most main roads are posted in a manner that defines the super majority as lawful it would be possible to reinstate respect of the traffic laws in general and possibly the officers that enforce them. However, If we post at a point where the super majority (85%) are defined as lawful by the number on the sign and then don't enforce against those who exhibit unlawful behavior unless they are in the top few percent, the message that is sent to the drivers is that the government doesn't respect it's own limits and they have little faith in their correctness. This will breed disrespect for the limits and the officers who enforce them….cont….
Mr. Mckrackin and I differ here, and I don't see any way we will ever totally agree.
I do not believe that the average driver will ever accept that driving at the limit +3 constitutes anything other than substantial compliance with a realistic limit that should never be penalized. It is too close to warrant sanctions in the eyes of the average driver. This is the level of "being over" that is so easy to happen with just a bit of downhill pavement. It is the level of being over that people who are following the limit very closely will use to complete a pass in less than a mile — or will use to put a bit of distance between themselves and other cars for the sake of safety.
I believe, and Mr. Mckrackin probably disagrees, that no driver would ever expect to get sanctions for driving at +1 to +4 over such a corrected limit, and would lose all respect for any officer or venue that tried to use that level of enforcement. It would not strike them as anything but abusive and predatory. If tickets were issued for +1to +4 above a correctly rounded 85th limit, I would expect enough of them to be challenged to clog up the courts to a total standstill.
I do not believe that the average driver would ever conclude the government does not respect its own limits if they do not issue citations for +1 to +4, I believe they will perceive such a small grace as totally appropriate and proof that the government in that area is acting in the most responsible way and is no longer trying to be predatory.
With our near complete differences in how we see drivers views of corrected 85th speed limits, I do not see how Mr. Mckrackin will ever totally agree on what should happen with enforcement.
So don't be fooled by Mr Walker's lip service about respect for the laws and/or the law enforcement officers. Mr Walker's plan neither wants respect for the law and the officers nor will it provide it. If the number on the sign represented the limit, and the speed, for those safe, sane, sober and competent drivers, that provides the greatest safety benefits. and was enforced as the number on the sign. The clear decisive message that the limits are correct, safe and reasonable, the motorists would respect them and the officers who cite the unlawfully proceeding drivers.
It would be really helpful if Mr. Mckrackin stopped the foolishly abusive personal attacks on my motives and statements – but I have learned to not let them interfere with my logical analysis of the issues.
Maybe police departments and officers in his area are totally different than in Michigan, but my views are in complete lock-step with the Traffic Services Section of the State Police, the department responsible for safety statewide. They respect me and I respect them, our views are virtually identical. If Mr. Mckrackin thinks my statements are "lip service" in wanting and knowing how to regain respect for traffic laws and the officers that enforce them, then he is just profoundly wrong.
American drivers will never accept, and should never accept, enforcement at +1 to +4 over a correctly rounded 85th limit. I believe that no legitimate police force would ever try to issue tickets for +2 on corrected limits. It would brand them as viciously predatory in the eyes of virtually every driver – whether ticketed or not.
We can, and should, manage the overall flow of traffic for safety and smoothness. That process should NEVER include trying to micro-manage every vehicle to absurdly fine tolerances of less than 4 mph.
Will there always be drivers who don't comply? yes According to the science there will be 15% of the speed distribution that exhibits unlawful behavior. According to the science those 15% are all adding risk of crash to the speed distribution and risk of casuatly crash(meaning injury or death) to the speed distribution at an exponential rate. If safety, and not just higher speed limits at any cost, is the goal the greatest safety benefits can be realized the closer you enforce to the number on the sign.
I agree with the above in overall principle. Where I disagree is getting the enforcement any closer than +5 to a correctly rounded 85th limit. Today's artificially low posted limits and grace allowances of 10, 15, or more mph to make ticketing practical are totally absurd. NO driver has respect for this system, and they shouldn't have.
"Higher limits at any cost" is a common phrase from Mr. Mckrackin, and it is totally false. The truthful phrase is "Correct limits at any cost" to end today's absurd chaos.
New item. I decided to take the time to review a lot of studies to put to rest the difference between posting speed limits correctly rounded up or down from either the 85th percentile speed or the top of the pace. I looked at 106 speed studies with a mix of slow city streets, urban/suburban collectors & arterials, rural surface highways, urban freeways and rural freeways. The studies are a mix of ones done by me, the State Police, MDOT, and the City of Ann Arbor. Here are the results.
# of
Cases
1 Pace 3 mph lower than 85th
4 Pace 2 mph lower than 85th
27 Pace 1 mph lower than 85th
42 Pace identical to 85th
28 Pace 1 mph higher than 85th
4 Pace 2 mph higher than 85th
106 Total
In 97 of 106 cases the numbers are the same or +/- 1 mph.
Using posted limits correctly rounded up from X3/8 & X4/9 or down from X2/7 & X1/6
# of
Cases
4 Using the pace posts limits higher — 1 is a freeway, 3 are city streets
95 Limits post the same using either parameter
7 Using the 85th posts limits higher — 6 of the 7 are freeways, 1 is a rural highway,
NONE are city streets (no over-posted city streets to "terrify" residents)
106 Total
In 95 of 106 cases there is no difference in the posted limit with either method.
There is no practical or safety difference between using the 85th or the top of the pace as the item to determine posted limits. I choose to support the 85th because it is a known term today with most authorities and much of the public who follow this issue, and it took decades to get it understood. Engineers have understood it for at least 70 years. I choose not to spend maybe a another decade re-educating the public and politicians about what the Pace means, since it makes no practical difference in what ends up on the speed limit signs.
I do explain both terms when I talk to people today, it does help a bit to get a "buy in" — but I see no practical reason replace the 85th with the top of the pace as the main factor and have to explain that whole methodology all over again.
If the Pace were the commonly understood term today, I would clearly have no objection to using it as the main parameter, instead of the 85th – but that is not the case. If the Pace were the commonly understood term, I would not try to overturn it or replace it with the 85th. The results are too close to make any practical or safety difference.
I hope this satisfies Mr. Mckrackin and anyone else who thought the Pace was a really superior parameter to use — it is not.
Of the 50 speed surveys where the pace was lower than the 85th, 80% would have resulted in slightly a lower number on the sign. So you can see why Mr Walker refuses to use this parameter. Proper engineering practices dictate that that the 85th percentile be used as a starting point and the several other parameters be considered one of which is the pace and median speeds
Of the 3 that had a pace 2mph above the 85th all would have resulted in a lower number being posted on the sign
of the 24 that had paces above the 85th by 1mph, 40% would have resulted in lower numbers on the sign.
It is obvious why Mr Walker and the NMA would have engineers disregard this important parameter and only consider the 85th percentile speed..
I see why Mr. Mckrackin reaches his conclusion that the pace is usually lower than the 85th from that data set. My data set was pretty wide, roads with 85ths from 25 to 82 mph and the balance was a LOT more even. I gave a copy of my data to the state police today and the officer (a trained accident reconstructionist and speed study expert) said the spread looked very normal to him. He expected the 85th and pace to differ by no more than 1 mph in most cases and the higher one can be either parameter.
Should you look at both parameters? Sure, and most of the time it makes no difference which you use. in RARE cases, if the parameters differ by a lot, you might favor one over the other, but that is not normally the case.
I choose to support the 85th because it has taken decades to get the term decently understood by many politicians and some citizens. I choose not to waste another decade to re-educate all those people of what the pace means, when 90% of the time it would post the same number on the signs.
My data set had not included the 12 highway and freeway studies I did in Texas in December on rural highways and freeways with 85ths from 61 (posted 55) to 84 mph (posted 80). (I couldn't find them quickly last night when doing the counts.)
# of
Cases
1 Pace higher by 2 mph
4 Pace higher by 1 mph
4 Pace and 85th the same
2 Pace lower by 1 mph
1 Pace lower by 2 mph
In 11 cases the posted limit would be identical. In one case using the higher pace results in a higher posted limit than using the 85th.
well I am sure if I put together a collection of 106 speed surveys the results would support my beliefs. in fact I have a number of speed surveys and the results are:
1 pace 4mph below the 85th
1 paces 3mph below the 85th
2 paces 2mph below the 85th
46 paces 1mph below the 85th
20 paces identical to the 85th
24 paces 1 mph above the 85th
3 paces 2mph above the 85th
Total of 97 surveys
Summary: I think we are really at the end of any useful debate with Mr. Mckrackin. He seems to want one of two solutions, and I do not believe either one can work properly.
#1 solution is to post the 85th/top of pace and enforce right above that number, so that the number on the sign is absolute and tickets would actually be given for +2 or +3 mph. I do not believe that Americans would ever accept such tickets. Large numbers would be fought in court and the court system would grind to a halt. In addition, the target pool would be absolutely huge and the temptation for venues to ticket for profit would be virtually overwhelming — at least until the court system ground to a halt.
#2 solution is the always round down and enforce with perhaps a 5 grace, ticketing at +6. This rounds down surveys that end in X3/8 and X4/9 and posts the limit too low for drivers to accept it as valid. I looked at a few examples and the posted limit rounded down from that 40% of the examples ends up in the range of the 55th to 65th percentile too much of the time. You cannot define 35% to 45% of all drivers as in violation and expect drivers to ever respect the limit as safety-based.
I do not see any reason not to post the real 85th, correctly rounded up or down, and end up with limits drivers will respect – limits that are a maximum of 2 mph off the real 85th. You then enforce at +5 which enforces versus an average of the top 5%, the ones whose speed alone MAY cause safety problems. Anything else leads to either potentially abusive enforcement or such random enforcement versus an enormous target pool that there will never be any safety value for enforcement. Both of those results also continue to degrade respect for posted speed limits, for traffic laws in general, and for the officers that enforce them. None of those results is acceptable to me.
Addition to information about solution #2 above. I researched 37 speed studies I had where the 85th ended in X3/8 or X4/9. In 19 of the 37 cases, the resulting rounded-down limit would be below the 67th percentile – the lowest recommended posted limit by the ITE proposal: http://www.motorists.org/speedlimits/home/a-recom... This 67th percentile level was also part of a failed federal bill to establish realistic speed limits many years ago. In 8 of the 37 cases, the resulting rounded-down limit would be at or below the 60th percentile, thus defining 40+% of the drivers as violators. Such limits are not acceptable and cause the justified disrespect we see today for artificially-low posted limits That disrespect can lead to disrespect of traffic laws in general and the officers who enforce them – another even more unacceptable result.
The bottom line is that most posted limits need to be set the correctly rounded 85th percentile (or at the rounded top of the pace) and enforced with a small grace. Only places with hidden hazards or very unusually high crash rates deserve special treatment. This will yield limits that drivers will respect, the enforcement will be versus the high flyers and the crazies who are well above the normal speed pattern, and our system of traffic laws and the officers who enforce them will regain the respect they deserve.
If the 85th percentile speed is the safest speed to be traveling at then why would we need to allow speeds above that to be lawful and or unenforcable? If you can't accept the speed limit that is posted on the sign even after it has supposedly been corrected to this safest speed and with accepting it comply with it then you deserve to suffer enforcement action for contributing to the degradation of the safety of the driving enviroment for everyone else using the roadway……
Because Americans would NEVER accept tickets at +2 over the posted limit. That is an absolutely hopeless wish of Mr. Mckrackin's that will never happen.
If they wouldn't accept being arrested for stealing does that mean we should make it awful to steal? Just because they will resist the enforcement methodology is not reason to not consider it. We have limited resources in both the police field and the emergency medical feild. I would rather stress the resources of the police than those of the emergency medical field. There have been many articles in medical journals written by doctors about how the severity of crashes has increased and they identify that as a society we need to dimminish the effects of traffic crashes. The most effective way to accomplish that is reduce travel speeds. cont…….
We may be getting to Mr. Mckrackin's real goals here – "The most effective way to accomplish that is to reduce travel speeds ….."
People who have studied this for many decades know that reducing overall travel speeds is not going to happen in the USA. We do not have even a small fraction of the police resources it would take to do this effectively. What we CAN do is make the flow smoother, reduce conflicts, reduce the crash rate, reduce aggressive driving/road rage, and restore respect for traffic laws and the officers that enforce them. I am only interested in practical solutions that work, not theoretical ones that have been proven to be a failure for 30+ years.
We know your real goal. The highest possible speed limits at any cost. There is a point in the risk curve where adding speed stops adding safety and begins to increase risk. If Safety was Mr Walkers goal he would encourage keeping travel speeds at or near the 85th percentile rather than promoting that the 85th increase and non enforcement of unlawful behaviors. If there aren't currently enough resources and jobs need to be created to help the economy then add police resources and do what needs to be done to keep our highways as safe as possible. Claiming there aren't enough resources is an excuse to allow speeds above the 85th percentile even though those speeds dimminish the safety of the entire speed distribution…..cont….
What are your goals if you will advocate allowing speeds above the 85th percentile that actually dimminish the safety of the entire speed distribution? Your goal certainly isn't safety.
Since 85th limits do not diminish safety, they raise it, the question is simply wrong.
The 85th limit itself does not raise safety. The increased safety that accompanies an 85th percentile speed limit comes from more vehicles traveling at like speeds and fewer speed variations. IF you then allow speeds in excess of the 85th and above the 95th, as Mr Walker advocates, the safety benefits you gained by posting the 85th percentile are negated by the safety losses of those you are allowing to exceed that "Corrected" speed.
This is playing with words, but worth a reply. We know that setting limits at the 85th tends to produce the lowest crash rate. We know that limits a bit below the 85th tend to have a slightly higher crash rate and those set way below the 85th tend to have even higher crash rates. So, does correcting a low limit to the correct 85th level raise safety? Yes, in my view, and for precisely the reasons Mr. Mckrackin states – more vehicles at like speeds and fewer speed variations. We should add – this improved speed distribution with fewer variances tends to reduce the conflicts between vehicles and THAT is where the improved safety really comes from.
OK so far, we agree on all the basics.
NOW, Mr, Mckrackin seems to want to find a way to pretty much stop most drivers from going above the 85th – but that is utterly impossible, whether the limit is set at the 30th as is common today, or at the 85th where it should be. The speed distribution is a bell curve and no matter what you do, it is completely impossible to get to the 85th and then have virtually all of the current 86th-99th percentile suddenly reduce speeds to get at or below the 85th.. It cannot happen, and it will not happen.
What DOES happen with 85th limits is that about 10% of the top 15% will be in the 5 mph interval just above the 85th. If we leave those pretty-safe drivers alone and concentrate our limited enforcement resources at the (average) top 5%, the 95th percentile and up — this pool is enough smaller that enforcement can have some real impact on behavior. When a 95th percentile driver gets one ticket for $150, they might not change behavior very much. When they get the second one for $150 + $600 more insurance, they are likely to take notice and modify their behavior. If they get a third one for $150 + $1,200 more insurance — you have a real chance to change that behavior for a long time.
The "safety losses" Mr. Mckrackin thinks negate the gains by posting the 85th just don't happen. The small number of crazies at the 95th and up are essentially the same with bad posted limits or good ones. The difference is that with correct limits, the enforcement is targeted correctly against those drivers whose speed alone may cause safety problems. This does NOT happen with bad limits, most enforcement goes against the wrong groups, either the safest possible drivers or those with only very slightly higher risks.
I am not looking for a way to STOP "most drivers" from exceeding the 85th because by definition "most drivers" are traveling at or under the 85th percentile speed. I would however like to attach consequences to the behavior of exceeding the "safest speed" That Mr Walker and the NMA attribute as the 85th percentile speed. Why do I want to have that behavior have consequences attached to it? because without consequences for the behavior of exceeding the number on the sign, in this case the 85th percentile correvted numbers, the numbers on the signs do not represent a limit. By defining the behavior of exceeding the corrected 85th percentile speed limit numbers on the sign as unlawful, you are informing ALL drivers what speed for that roadway is reasonable and safe. By then allowing ANY substantial portion of those who choose to exceed it to proceed without consequences you diminish the definition of what is safe and reasonable and encourage the behavior of exceeding that speed.
Lets look at Mr Walker solution. He wants us to post the 85th rounded to the next 5mph increment and then not enforce aginst 66 to 93% of the motorists who would violate that corrected and much increased speed limit. He cites better traffic flow, reduced conflicts, reduced crash rates reduced aggressive driving and restoration of respect for the laws and officers who enforce them…..cont….
I want 85th limits, correctly rounded up OR down and then enforce versus an average of the top 5% (range about 2% to 8%) because those are the drivers whose speed alone MAY cause safety issues.
I proposed a system that would round up or down from the 85th percentile speed dependant upon where the top of pace was. If the top of pace was above the 85th round up if the top of pace was below the 85th round down. However, like the proposal of using the top of pace number Mr Walker rejected this because he knows this will result in slightly lower speed limits given it is not arbitrary like his methodology. I believe he rejected it because I wanted the number on the sign to be enforced and I see no reason where an 85th limit that has been rounded up should have an additional enforcement grace.
We have discussed this many times and I choose to use just the 85th because it is the known term and it took a LONG time to get the meaning understood by lay people and politicians. I choose not to lose maybe another decade while we try to re-educate the public and politicians about the meaning of the term Pace.
In 4% of the cases, using the top of the pace gets a higher posted limit and in 6% using the 85th gets the higher limit – both by only 5 mph of course. In 90% of the cases there is no difference. So, in 94% of the cases, the limit will be the same or lower with the 85th – I go with the 85th.
Mr. Mckrackin wants to falsely say my method is arbitrary but people who have read the literature know is it anything but arbitrary. It is the method of choice by most unbiased researchers for the last 70 years. This mixed method of rounding by comparing the pace with the 85th is Mr. Mckrackin's invention and I see no support for it in the literature.
I have read the literature! I know that your methodology would result is a system just as arbitrary as the one we have now, because it uses essentially the same approach with the exception that the numbers on the signs would be higher. All those abuses that you fear in our system currently would remain with Mr Walker's system. My Methodology would put a distinct line between what behavior is lawful and what behavior is unlawful and punish those who choose to exhibit the unlawful behavior.
Like I have pointed out many times Mr Walker and I agree on where the safest place to post is and ALL the disagreement comes into play when we discuss how to enforce the limits. Mr Walker would have NO enforcement if he could and we all know what value the speed limit would have in that world.
This is just a load of irrational nonsense, and any reader of this thread will take it as such. I want the enforcement of a properly rounded 85th limit to be at +5 and up — so it is versus the average of the top 5%. It is totally false on Mr. Mckrackin's part to try to say this means I want NO enforcement — that is just a nonsense statement that Mr. Mckrackin and every reader of this blog knows is totally false. Why he would waste the time to post such nonsense is a mystery.
It is irrational nonsense to agree with Mr Walker as to where the safest place to post the speed limits at?
Using Mr Walkers methodology will not accomplish a reduction of conflicts because he is allowing traffic to choose speeds outside the pace and not be punished for the unlawful behavior. This will encourage the sped distribution to spread out and increase the chances of conflict. Likewise allowing speeds that add risk to the entire speed distribution will not decrease the crash rate. Because his plan allows for vitually no enforcement against the unlawful behavior. although it may be accepted because it doesn't punish the unlawful behavior of exceeding the corrected speed limit that is by design supposed to maximize safety, it will never be respected.
My method, the method supported by the ITE, SAE, TRB, 17 states, Parker, Cirillo, and many more does reduce conflicts by smoothing the speed distribution — it is one of the major key elements of why it works. Mr. Mckrackin's statements above that it does not reduce conflicts or spreads the speed distribution are simply wrong. You get 85% compliance (by definition) and an average of 10% will be in the next 5 interval. You enforce versus the top 5% on average. It works.
It will never be respected because as soon as it is apparent that it doesn't matter that you exceed it or that you won't be punished for exceeding it no one will respect it. Just as they don't respect the limits we have today because there is such a huge difference between the number on the sign and the number that gets enforced. To stop the 30+ year of failures we need to enforce closer to the number on the sign not further away. I am curious how a "theoretical solution" is proven to be a failure for 30+ years if it never made it past the theoretical stage and actually became tested. We know from the 60's that posting the 85th percentile speed failed then, we also know that allowing graces above the posted speed limit leads to failure of the speed limit. What are Mr walkers goals if he is blatently promoyting failed policies as the best course of action coupled with non enforcement against unlaful behaviors?
Mr. Mckrackin's comments above seem to assume that people will slowly adapt to the new limits and push the point up to the enforcement level. This does not occur with correct limits. I agree to enforce closer to the number, AFTER the new limits are posted. I want a correctly rounded 85th, up or down, and a +4 grace from the sign – ticket at +5.
The use of 85th limits in the 1960s was NOT a failure, it brought some uniformity and greater safety. The fatality rates were much higher then for a long list of obvious reasons: less safe cars, less safe roads, almost no belt use, less advanced trauma hospitals, and many more minor reasons.
MANY venues have claimed to enforce close to the number on the sign, whether a good limit or not, and it doesn't happen — the numbers on high volume roads make that impossible to achieve.
Human psychology tells us differently. ask yourself this question. If the limits were posted at 65mph and you were allowed to drive at 70 or 75mph how fast would you drive. Given these parameters with a speed limit of 65mph how fast would you drive? please answer the poll[polldaddy 2739699 http://answers.polldaddy.com/poll/2739699/ polldaddy]
That is not an endorsement by me to allow artificially low speed limits. However, it is cause to question allowing speeds above the 85th percentile or speed limit set using the 85th percentile. If that means stricter enforcement of the numbers on the sign to make the higways safer then who cares that drivers won't accept the consequences of their actions. THE ONLY WAY to fix the system is by stopping the common behavior of exceeding the posted speed limit. If you are going to allow speeds in excess of the posted limit then the system will not ever get fixed. If that is the path you choose then there is no reason to correct the speed limits, because the new limits and system will be exactly the same as what we have now except for higher speeds. All of the abuses that we suffer now will still exist but at higher speeds. the NMA will have accomplished nothing for safety. the only thing that will have changed is the numbers on the signs. it will not be any safer, If increased safety is the goal then Mr Walkers methodology will not work. One needs to question if it will not work why does he insist on it……cont…..
Let me give a clear example of why one of Mr. Mckrackin's methods is simply wrong. Take a place with an 85th of 72 mph and round it correctly to 70 for the posted limit. Enforce this at 71 or 72 mph and you ticket the absolutely safest drivers on the road, the ones with the lowest possible crash risk. Enforce it at 73 or 74, and those drivers have an infinitesimally higher crash risk than those at 71 or 72. This situation is unacceptable for any reason. Mr. Mckrackin often suggests that correct posted limits with a small grace will lead to higher actual speeds, and that is not the case (other than a one-time correction on freeways which were grossly under-posted and the roughly 5 mph creep on rural freeways each 10 to 20 years).
Mr Walker knows very well that what he has attributed to me above is not what I believe or advocate and is simply deepening his intellectual dishonesty.In this given example I would round down to 70mph to post and then allow 4mph grace and enforce starting at 75mph. which enforces against the drivers who are increasing the risk of crash to the entire speed distribution and are adding risk of injury or death to the speed distribution at an exponential rate. I do not suggest that corrected limits enforced with a small grace will lead to increased speeds. I suggest that correcting the speed limits and then not enforcing against 66 to 93% of the unlawfully proceeding motorists would lead to higher travel speeds(incidentally that is what Mr Walker advocates).
The answer above of post 70 and enforce at 75 is one place we agree. It is the answer I expected and hoped I would get. Call this point A. Now lets make the issue a bit more complicated. On this same freeway, five miles down the road at point B, there is an area where the 85th is 69 mph. Ten miles further down, the 85th is 71 mph at point C. Five miles further it is 68 at point D. Ten miles further it is again 72 at point E. How do you post and enforce at points B and D? (I am assuming you post 70 and enforce at 75 at C and E.) Note that limits which bounce up and down for reasons that are not obvious to the drivers are undesirable from many points of view, including safety.
We Agree more than Mr Walker will admit. Our chief point of disagreement is on enforcement. Although Mr Walker portrays my argument as I am against raising speed limits. Reasons??? He and the NMA want their way and only their way. Considering that they are all segments of the same roadway I would compile the 85ths along the length of it and use the average 85th to determine the correct posting of the entire length. The average 85th is 70.4mph I would post 70mph and allow 4mph and start writing citations to those traveling 75mph or greater
This is the correct answer — to post the road at 70 with the example surveys quoted – and is EXACTLY what I would do, enforcing at 75 and up.
I would NOT change that recommended posting via the pace, because the number of cases where the pace and the 85th differ by enough to change the posted limit are tiny. I am just going by the above post's exact words, but Mr. Mckrackin says if the top of the pace were 65 mph (with an average 85th of 70.4), he would consider a lower posting or if it were 75 he would consider a higher one. In 118 cases, I saw only one example with a top of pace 3 mph different than the 85th and only 10 more with a top of pace 2 mph different from the 85th. In 107 of 118 cases, or 91%, the top of pace was the same or +/- 1 mph from the 85th – with examples very evenly split above and below.
IF the Pace were the known term, I would have no problem using it at the parameter. But, the 85th is the known term and I prefer not to waste maybe a decade changing people's understanding of the right thing to do. In those 118 cases, rounding from the top of the pace posted a 5 mph higher limit 4% of the time and rounding from the 85th posted a 5 mph higher limit 6% of the time. In 90% of the cases the posted limit was identical. This is just "much ado about nothing".
Let's now alter points A and E! A has a measured 85th of 73mph and E has a measured 85th of 74mph how would you post?
That is a VERY good question by Mr. Mckrackin and now you get into some serious issues of engineering judgment. We now have 85ths where A=73, B=69. C=71, D=68, and E=74. There are several answers possible and I am going to assume here this is a rural freeway.
Considerations.
First – the engineer may correctly say that it doesn't make much difference whether you favor the 3 slower readings and post 70 mph or the 2 higher ones and post 75. It is unlikely that posting 75 would "speed up" the distribution at B through D by any significant amount, and it is unlikely that posting 70 would slow down points A and E at all. (This would be particularly true if the area was already posted at 70 and you are resurveying at a 5 to 10 year interval for changes.)
Second I think most engineers would tend to post 70 and I don't have a real problem with that. One would hope that officers would not use points A and E as traps, knowing they are the best points in the area where sight and stopping distances allow drivers to feel safe and comfortable a few mph above the speeds at points B through D because the road is better in those areas.
Third, However, if the area is now posted at 55, then I would probably post at 75 — knowing that points B through D will likely rise by a few mph and the rounding to 75 is likely to be more accurate a year later and not require another change. If the points B and C have shorter sight lines and safe stopping distances, they are likely to remain somewhat slower anyway. Maybe they move to B= 72/73 and D= 71/72. A and E probably move to the 74/78 range.
Fourth If you post 75, you will tend to have more diversion from rural surface highways to the freeway and more of a safety gain for the area as a whole.
Fifth, I think most engineers would see what the distributions were at points before A and after E, if the road is really longer on one or both ends. It is appropriate to aggregate and average surveys over longer distances to avoid rapid posted limit changes — IF the numbers are not too different.
Sixth, In general on a freeway, there is no problem to post a bit higher for the longer stretch, and then use advisories for the areas where the 85ths are lower. This is what Utah did at the end of the NMSL when they has a pre-approved law by the legislature to go to 75 on rural freeways as soon as the NMSL was repealed. The safety chief of the Utah DOT told his people to go find the handful of places where advisories for 70 or 65 would be appropriate and post those FIRST, then post the rest at 75.
NOW, if this is an urban freeway, I would think the engineer should probably favor the more conservative view and post 70.
Notice how Mr Walker was fishing for me to round segments down. This is a tell tale sign that he really has no functional understanding of what my position actually is. However since they are segments of the same roadway they should NOT be posted separately and the speed limit along this roadway should have continuity, If there are places that need to be posted lower for safety reasons,speed advisory signs should be utilized…cont…
I was fishing for nothing, just presenting the various ways engineers could look at this and voicing my opinion of how they would deal with it. Mr. Mckrackin doesn't even know how to deal with complete and honest answers without looking for deviousness under the rug that isn't there.
I probably look for deviousness in your answer because you are constantly mis-stating, misrepresenting and misattributing my statements and my position. Historically you have proven to place your agenda above an honest answer as do ALL NMA members.
I did notice that Mr Walker would use the faster segments of that roadway to increase the speed limit an additional 5mph on the entire roadway, even though the average 85th percentile did not support doing that. Like I have said many times the highest possible speed limit that can be rationalized. Scientifically the data supports the solution I gave. So why then would Mr Walker support a speed limit 5mph above that, if he is in favor of setting the limits scientifically? The answer is he only pays lip service to using science and only uses select portions of the science that he can manipulate to support the highest speed limit he can rationalize. He also only pays lip service to safety because if the science is telling us that the greatest safety benefit is to have at a point below that which Mr Walker will allow, he can't possibly be working to maximize safety.
Now also note by adding 1mph to two of the segments Mr Walker immediately suggests that a speed limit of 75mph would be more appropriate along the entire length of the roadway even though the segment 85th percentile speeds do not support that. Further the Pace speeds along this roadway would not I am sure support posting 75mph. Mr Walker also supports aggregating the surveys before these points and after these points even though in this example we do not know what they would show us. Given the amount of information given us here if we aggregate Mr Walkers example the average 85th is 70.4mph and if we aggregate my example the average is 71mph yet Mr walker feels that we should move all the way up to 75mph speed limit. then he would also advocate not enforcing the next 4mph and begining enforcement at 80mph…cont…
I presented several versions, each with an explanation.
Since pace speeds are +/- 1 mph from 85ths in 90% of the cases, Mr. Mckrakin's statement about the pace not supporting 75 mph is utter nonsense.
Last point here is that Mr. Mckrackin seems to almost always assume that when you have a choice to post the lower or higher 5 mph interval, that the lower is better. If you take into account things like diversion and level the new limit is coming up from, this thought is often not true.
I assume that the lower 5mph increment would be better than the higher 5mph increment given that both 5mph increments have similar crash incidence probability(they are approximately the same distance from the 85th percentile speed) because science tells us that the higher 5mph increment is at least twice as likely to result in an injury or fatality at speeds above 37mph(but then this is some of the science Mr Walker and the NMA ignore)
What are the advantages of allowing speeds of upto 79mph when the measured average 85th is 71mph. If safety is the goal then properly rounded the speed limit would be set at 70mph and only74mph allowed and citations issued at 75mph and above to the crazies. As Mr Walker pointed out the 90th percentile is only about 1mph above the 71mph 85th and the 95th percentile speed is about 5mph above the 85th that means the average 90th percentile would be 72mph and the average 95th percentile would be 76 mph. Mr Walker also told us that those who present a real danger are the top 5% or those above the 95th percentile. If the average 95th percentile speed is 76mph then by allowing upto 79mph Mr Walker is advocating allowing unsafe speeds. Why would he do that if his goal is safety?…cont…
Rounding is a fact of all speed setting, and you don't trick it to achieve arbitrary results.
But, we are done Mr. Mckrackin, you just don't get it.
On the contrary I "get it" just fine. However my unwillingness to compromise safety for speed makes me the enemy of the NMA even though I support corrected speed limits. I have pointed out using YOUR example how you ignore the very science you preach.
Mr Walker advocates allowing 8mph over the average 85th percentile speed, 7mph over the average 90th percentile speed(point where Mr Baxter tells us safety drops off) and 3mph over the point where he tells us speed has begun to effect driver safety. Looks alot like he just wants as high of a speed limit as he can get.
We are done.
I would expect nothing other than hostility from someone who has been proven to disregard the science he is preaching Safety couldn't possibly be your goal if you would choose to allow speeds 3mph above the point you suggest and 7mph above the point Mr Baxter suggests is where speed is degrading safety.
One must question, would someone who is working for increased safety benefits insist on a plan that has no possible chance to increase safety? Would someone who's agenda is to increase speed limits at any cost suggest such a plan that would effectively only increase the numbers on the signs and actually degrade our safety?
Because the plan I suggest IS the science that has been proven to work for decades to improve safety. The goal is not to "increase speed limits at any cost" as Mr. Mckrackin falsely suggests, it is to post the 85th percentile speed limits that have been shown for decades to improve safety.
The plan you suggest is a perversion of the science and using YOUR example above on where your suggested method would post shows us that it would allow speeds 3mph greater than the point you told us is where the safety begins to degrade because of speed and 7mph above the point that the president of the NMA tells us is the point where safety begins to degrade as a result of speed. Your method pays lip service to the science and ignores it when you would prefer to do something other than what the science dictates is the safest course of action
In order to fix the system we need to stop allowing graces above the speed limit. I would have no problem accepting a system that always rounds up from the measured 85th percentile speed as long as it wasn't coupled with another allowance like an enforcement grace. If we were to use Mr Walkers methodology of posting and enforcing the speed limits we would be posting above the 85th all the time and then enforcing at above the 95th percentile speed in many cases as high as the 98th and 99th percentile speeds. This would be a huge waste of our nations resources…….cont
Americans will NEVER accept tickets at +2 over the posted limit. That is an absolutely hopeless wish of Mr. Mckrackin's that will never happen.
at some point the law has to be the law and those who break the law need to be held accountable for their actions. if the limits are corrected there would be no reason to allow speeds above the corrected speed limit, who cares if the people WANT a grace, theives want to be able to steal and get away with it but we don't allow it just because they want it.
Speed limit enforcement for Mr. Mckrackin can be an absolute – ticket at +1 or +2 as a principle. Traffic safety researchers know this is not a plan that could improve safety. We cannot micromanage the speeds of every car, we simply do not have and never will have the resources to do this. We CAN manage the overall flow with common sense and target the enforcement versus the small percentage of drivers whose speed alone may cause safety problems.
again Mr Walker misrepresents my position on this. Big surprise an NMA member misrepresenting something I said. If you work on your reading comprehension Mr Walker, then go back and reread you will see that I ONLY advocate citing that close to the speed limit AFTER the limits are corrected. This shouldn't be a problem if increased safety is the reason for reposting to the 85th and enforcing the limits. If your agenda is something other than safety, you will advocate letting drivers above the 85th proceed as if they were being compliant even though they are not…….cont…..
Mr. Mckrackin falsely accuses me of misrepresenting his position, but I do not do that. I just carry his statements into what they would have to mean in real life. He says above "at some point the law has to be the law and those who break the law need to be held accountable for their actions. if the limits are corrected there would be no reason to allow speeds above the corrected speed limit" IF you have a corrected limit set at the 85th, and THEN you do not allow speeds above the number on the sign — what possible other meaning is there than to ticket at +2 or +3, or even +1 for that matter? 85th=70, pace is 61-70, posted is 70 —– IF you ticket those who break the law, what possible other meaning is there than the conclusion you will ticket those at 71, 72, 73, & 74 —- plus those at 75 and up that are far enough out of the pattern to warrant sanctions? You cannot have it both ways Mr. Mckrackin. IF you make pronouncements that ANYONE above a posted limit deserves sanctions, AND you post correctly rounded 85th limits, then you WILL issue tickets at +32 or +3, or maybe even +1. If you think this analysis is a misrepresentation, then please clarify how you would post and at what level you would enforce the limit where the 85th = 70 and the pace is 61-70. Please be specific.
I sa1st of all I said that drivers who exhibit the behavior of exceeding a corrected speed limit "SHOULD BE HELD ACCOUNTABLE FOR THEIR ACTIONS". I did not say that in holding them accountable that they must be santioned or santioned at the same level as those who are well out of the pattern(the crazies and high flyers). So YOUR conclusion would be flawed in that you conclude i would have drivers ticketed for 1,2,3,4mph. Stopping them and warning them that they are exceeding the lawful limit and approaching speeds that degrade safety is just 1 possible enforcement action that does not include ticketing and it allows drivers who are +1, +2, +3 or +4 know that they are in violation of the law and where the law defines them as unlawful instead of just allowing them as if they were being compliant even though they are not. +32 in your example would likely recieve a ticket, the +3 may recieve a ticket or a warning at the officer's discretion and the +1mph would likely recieve only a warning. All three are made aware that their choice of speed was not lawful which may modify their behavior even though they may not have been sanctioned.
You have stated that venues under post limits and that this has zero positive effect on safety. I submit that the safety effect is tied to effective speed limit and not the posted speed limit. As such reposting to the 85th would have a small positive effect on safety, because it is redefining safe unlawful drivers as lawful(I support this), without altering the speed distribution. The small safety gains would be realized as long as the traffic stream tightens and more motorists choose to become part of the pace by traveling at or near the 85th percentile speed. If you then atificially allow speeds greater than the 85th percentile and the posted limit you will reintroduce the phenomenon that led to the spread which drew the safest portion of the risk curve up and away from the speed limit in the first place and you will NEGATE ANU safety gains that you achieved by posting to the 85th percentile in the first place…..cont…..
You have stated that venues under post limits and that this has zero positive effect on safety. I submit that the safety effect is tied to effective speed limit and not the posted speed limit. As such reposting to the 85th would have a small positive effect on safety, because it is redefining safe unlawful drivers as lawful(I support this), without altering the speed distribution. The small safety gains would be realized as long as the traffic stream tightens and more motorists choose to become part of the pace by traveling at or near the 85th percentile speed. If you then atificially allow speeds greater than the 85th percentile and the posted limit you will reintroduce the phenomenon that led to the spread which drew the safest portion of the risk curve up and away from the speed limit in the first place and you will NEGATE ANU safety gains that you achieved by posting to the 85th percentile in the first place…..cont…..
The safety effect is severely damaged by under posted limits because it destroys the respect people could have for traffic laws in general being enacted for safety purposes, it destroys the respect people should have for the officers that enforce them, it raises the probable crash rate slightly, and it tends to spread the speed distribution unevenly. Mr. Mckrackin seems to agree with some of these results, as shown by his comments above. What Mr. Mckrackin does not accept is the absolute impossibility of changing driving behavior for large numbers of vehicles so that it nearly turns the 85th percentile speed into the 100th — with almost nobody over the 85th. This will never happen. He does not accept that the next few mph above te 85th will always have a significant number of vehicles, roughly 10% of the total, and that they are of little danger – especially on a freeway. He seems to accept that safety improves when more people travel in the pace (even when the pace is well above today's artificially low posted limits), he does not seem to accept that the next few mph just above the pace are almost equally safe and that we should focus enforcement on those well above the pace — roughly the top (on average) 5%.
Respect for the law is damaged by allowing speeds greater than those posted on the sign(ironically you support doing this). As respect for the law is lost drivers search for the speed that is allowed by gradually exceeding the posted limit. As individual speeds increase beyond the posted limit the pace, mean and 85th percentile speeds all gradually increase and damage the safety benefits of driving at the posted limit. It is not my intent to change the 85th percentile speed into the100th percentile speed. However I cannot support your attempts to change the 8th percentile into the 50th either. If we follow your methodology that is exactly what will happen. Unlawful behavior needs to be identified and the drivers exhibiting it must be warned that they are acting unlawfully and increasing the crash risk, risk of injury and fatality to every driver who shares the roadway with them. This cannot be accomplished by allowing their unlawful behavior to be treated as if it were lawful. Treating unlawful behavior as if it were lawful can only result in more drivers exhibiting it. If you plan to only take enforcement actions against the top 5% then posting a number that defines 15% as unlawful is a mistake.
Mr Walker'splan exchanges safety lost by underposting for the safety lost by allowing speeds inexcess of the 85th percentile(or NEW CORRECTED speed limit). This should be obvious to anyone who is working to promote a safer driving enviroment, however Mr Walker finds it an unacceptable loss at speeds below the 85th, but totally acceptable at higher speeds(even though the safety risk lost is greater than the losses below the 85th). Why would someone supposedly working FOR greater safety hold such a position? The answer is that he is not working for greater safety he is working to forward the NMA agenda of higher speed limits at any cost.
It should be obvious to anyone that with corrected limits set from correctly rounded 85th speeds, that tickets for the next few mph above the posted limit will never be accepted by the public —- AND that those tickets are worthless from a safety point of view. There will ALWAYS be people in the next few mph above the 85th, the numbers are huge on high volume roads, and the chances for close enforcement to change that speed distribution is nil, zero, zip, nada. We COULD focus enforcement at the roughly 5% at the top and the numbers are sufficiently smaller that we could change behavior in that group over time. THAT would improve safety. Giving one ticket every 4 or 5 years to somebody 4 mph above the 85th is just an annoying road tax that convinces the receiver the government is after their wallet and not safety. Such a result is not a behavior changing event.
It should be obvious to Mr Walker that allowing unlawful behavior to exist as if it were lawful can have no other result other than more drivers exhibiting it. It is not my intent to change the speed distribution through enforcement . However, not enough enforcement will have negative impact upon compliance(how can you expect a motorist to respect a law that you don't respect enough to enforce?)
If Mr walker is working towards safer roads why does his methodology allow for non enforcement of upto 94.4% of the drivers who would violate the speed limit? I ask you is that the agenda of someone promoting safer driving enviroments or the agenda of someone who is looking to drive at faster speeds without having to worry about being caught at an unlawful speed or cited for such a violation? I am all for increasing speed limits to reasonable limits to meet with the comfort and safety improvements of today's vehicles, however those increases must be reasonable to ALL the roadway users. allowing speed limits of 85mph and then an additional enforcement grace that allows 90mph before any action is taken is not reasonable for all the roadway users and may have unintended consequences.
Actual 85th percentile posted limits, correctly rounded up or down, tend to produce the lowest crash rates and the smoothest traffic flow – so that is what I support. Rural freeways safely and easily accommodate wide speed differentials when posted correctly at the 85th, so Mr. Mckrackin's desire to impose some artificial and unscientific items into the formula is not warranted. If Mr. Mckrackin ever drives in Europe, he will notice that German Autobahns have 62 mph limits on trucks with 120 mph cars going by, with a lower fatality rate than US Interstates. IF the hazards are visible to the average driver, then arbitrary changes to the formulas to post limits are counter-productive and likely damage safety. There are many far west freeways where the 85th is at or near 85 and cars at up to 89 mph do NOT create any safety issues. I just saw a few of these in February, on roads now posted at 80. There were only about 1% of the vehicles at 90 or higher and they tended to be absolutely alone when measured. Mr. Mckrackin is afraid of unintended consequences that tend not to happen.
I am not arguing that corrected limits will not provide the lowest crash rates or smoother traffic flow. I am saying that if we allow speeds above the corrected limit you have skewed the results to the negative side. If you set the speed limits to the 85th and then allow speeds above the 95th to go unpunished you are misrepresenting the science because theACTUAL limit that is enforced is not the 85th percentile it is the speed above the 95th percentile that you are allowing……..cont…..
Since no legitimate venue tickets at +1 or +2 or +3, the fear of "… you will have skewed the results to the negative side." simply does not occur. Corrected limits do NOT skew the results negatively, and neither does allowing a small grace above them. These are theoretical fears that do not occur.
Allowing speeds above the 85th or (corrected limit) will skew safety benefits to the negative side. If you want to fix the system you will not rationalize reasons to allow speeds above the 85th percentile speed(new corrected speed limit). If your agenda is to simply have higher speed limits then your plan makes sense, even though it provides no safety gains over what we have now. You call them theoretical fears as a mechanism to rationalize ignoring them. If they are truly unimportant then it does no harm to recognize and consider them. BTW Utah has stated that in reposting to the 80mph they will enforce strictly to the numbers on the sign. So does the NMA consider it a victory having the speed limit increased or a defeat because the limit is now enforced without a grace?
I do agree we are ready for higher speed limits in this country but I believe they should be posted at the top of the pace not the 85th percentile and if they are to be posted there "in the name of safety" then they should be enforced very close to the number on the sign to secure the safety benefits.
I have repeatedly pointed out that the 85th and the top of the pace tend to be the SAME number, or within +/- one mph in most cases. Mr. Mckrackin seems to think the top of the pace is a better number to use, but since it is usually the same number, this is mystifying. I would have NO problem using the top of the pace instead of the 85th, it would normally put the same number on the signs. I prefer the 85th because it is a known term and I do not want lose another decade educating the politicians what the "Pace" means. I also agree to enforce much closer on corrected limits than we do on today's grossly under posted limits, and my preference is to start ticketing at +5 to the corrected limit. I do not think that tickets for +2 or +3 would ever be practical or accepted.
Lets do another specific example, if you would Mr. Mckrackin. The 85th is 72, the pace is 63-72, the limit is set by correctly rounding down so the posted limit is set at 70. At what specific level do you enforce?
If Mr Walker wasn't misrepresenting the autobahn statistics I would have a little respect for him. There are reasons why the speed differentials work on the autobahn and speed is not one of them. There are things present in the european system that are not present here in the USA. MR Walker cites the risk curve and the 85th percentile as being the safest point on that curve. The science he is citing uses the ideal that fewer variances in speed lead to fewer conflicts. Then Mr Walker cites the Autobahn as an example of large variances that don't result in higher fatality rates. What is the actual crash rate of the autobahn compared to our crash rates? The NMA will show you comparisons like this which are intellectually dishonest . Putting these comparatives into context and comparing them would show just how dishonest Mr Walker, Mr Young and the NMA are. They want increased speed limits and increased allowable travel speeds, They will try to accomplish this at any cost including lying to you, misrepresenting facts or dishonest comparisons.
Mr. Mckrackin should purchase and read Mark Rask's book "American Autobahn". The safety data for the Autobahns compared to US Interstates is quite clear, and none of it is dishonest. The 85th on derestricted Autobahns is just under 100 mph. Note the data is from the mid-1990s, but I have been in touch since with some German contacts and the data has remained pretty stable. NOW, to stave off an objection in advance if Mr. Mckrackin actually reads the book, I do NOT believe the US is ready for derestricted freeway speeds and we may never be ready. Mr. Mckrackin is right that there are some differences in Europe, including much stiffer requirements to get a driver's license and MUCH better lane discipline on freeways. We are ready for legitimate 85th posted limits, enforced with a small grace.
Comparing the Autobahn to our interstate system is an intellectually dishonest comparison that many NMA members will use. 1st off the full length of the Autobahn is not unrestricted, that is a myth. Much of the Autobahn has posted speed limits. Even the portions that are unrestricted carry a "suggested" speed limit of 130Kph (80.77Mph). Notice that Mr Walker will state he has been in contact with "German contacts" and then implies that they had informed him that the data has remained pretty stable. What does that mean? Did the "German contacts" actually give Mr Walker any data? Mr Walker is using our inability to examine the hearsay of some "German contacts" to give us his opinion without having to reveal anyverifiable source. Something that MOST NMA members will do when discussing this subject. …cont…
I could go back into my email and find the data from the German contact, but I choose not to take the time to satisfy just Mr. Mckrackin. Most people on these forums take me for a very straight shooter who speaks from knowledge and 47 years of study of the issues. If Mr. Mckrackin chooses to question my truthful rendition of such things, that is his right, but he is simply wrong.
I never said the whole Autobahn was derestricted and anyone who has read my posts will know that. SOME comparisons are valid, others are not. That is why I do not support derestricted limits in the USA.
If those contacts have provided actual data I'd love to get the opportunity to examine it! (because it doesn't exist). If Mr Walker in fact was in contact with "German contacts" and they indeed indicated that the data was stable, why then isn't Mr Walker telling us what the 85th percentile speed of the derestricted Autobahn is today? Instead he uses a figure from the mid 1990's (at least 10 years ago). Also notice that Mr Walker does not separate the derestricted data from the restricted data.He implies that the Autobahn is safer because it allows higher speeds, but fails to show us that the derestricted areas are safer than the restricted areas. For all we know the fatality rate on the autobahn would be zero if it were all limited as to speed. Also a point about the derestricted autobahn that doesn't get mentioned is the percentage of crashes that cause death or injury. I'd be happy to read that book, maybe you could send me your copy?…..cont….
See above, I will not spend the time to satisfy just Mr. Mckrackin.
The Autobahns are slightly safer than US Interstates for many reasons. Lane discipline is MUCH better, drivers are generally better trained, people KNOW to watch for high speed variances so they LOOK before they pull out, people open a lane for oncoming traffic at entrances wherever possible, most vehicles are under EU safety rules which are better than the federal FMVSS (tires, brakes and suspensions being the biggest differences), and many other more minor reasons. The whole point of the comparison between the Autobahns and the Interstates is that higher speed do NOT necessarily produce higher fatality rates – as is falsely claimed by the "safety lobby" in the USA.
American Autobahn is available from the NMA Store for $19.95 for non-members, $9,95 for members. The book was published in 1999 and the data charts go to 1997 in most cases. I checked with German sources and Mr. Rask to see if the data was still basically valid sometime about 2005, but I am not willing for Mr. Mckrackin's benefit to search that far back in my email files to find the precise quotes. Other readers will accept that my comments are true. However, when Mr. Mckrackin claims above ("because it doesn't exist"), it is just another baseless personal attack that most readers will ignore.
FYI, in recent years, German authorities have made it virtually impossible to get things like the official speed data on their roads, so really precise data is no longer available from official sources to see the exact numbers today. I HAVE personally driven there, and the speed distribution ranges from the late 1990s felt very similar in 2007 when I last drove there.
If it is so difficult to get the data then you can't make a correct comparison so all we have to use as a comparison is your seat of the pants feeling that it was similar in 2007 compared to the 1990's. If you feel this book will change my mindset then you need to purchase it and send me a copy, because I will not support the NMA by purchasing it from their store.
Then buy it from another source, it is not worth it to me to buy one for you. Note: you will NOT like the book, Mr. Mckrackin. And I do not like parts of it, we are not ready in my view for derestricted limits in the USA.
I find it very interesting that you will see a large number of Mr. Mckrackin's comments below deleted by Mr. Mckrackin. That leaves the replies a bit less informative, because the exact language of his comment is gone. However, most people following these threads will likely be able to remember or work out what I was replying to in the now-deleted comments.
Now consider that I did NOT delete any of my posts on this board. Also consider that Mr Walker has been the main counter argument and he attributes me as removing my own posts which leaves me to conclude that not only has the NMA censored my posts but that they have done so at the bequest of Mr Walker.
I was going by the text in the blog which seemed to indicate that Mr. Mckrackin had come back and deleted his own comments. Under no circumstances would I want to delete one of his comments to which I had replied. I WANT the readers to see the contrast between us, not to hide it.
I would attribute the problems to some sort of computer glitch on the server where this is outsourced. The accusation of censorship is complete nonsense.
I should quit here with another of dozens and dozens of unfounded accusations by Mr. Mckrackin, but I choose to reply.
Apparently me having accused the NMA of censorship was enough f to motivate them into retrieving and restoring the posts that had been deleted through "some sort of computer glitch on a server not maintained by the NMA" please the "it's not my fault" defense only goes so far. Ironically that is the same reasoning that the NMA uses to advocate that speed limits not be enforced. It isn't the motorists fault that he was exceeding the number posted on the sign that anyone with 20/40 uncorrected vision can easily read.
I also find the timing of this so called "computer glitch" to be extremely suspect. Just by coincidence when Mr Walker chooses to stop corresponding and responding to me a computer glitch wipes my contributions from this blog.
Note the disclaimer that preceeds the narrative if you follow the link Mr Walker supplied for us. "It should be noted that this report from the 4M-25 Committee on Speed Zoning, a part of the Institute of Transportation Engineers, is a draft version and is not yet an official ITE recommendation. Permission to post this on this web site was granted by the committee." This draft version was written in January 1996 and is not an official ITE recomendation. Why is it NOT a recomendation? and why, if this led to an official speed zoning recomendation by the ITE, isn't that recomendation here on these pages instead of this draft?
I would venture to accuse that this draft has been altered to support the agenda of the NMA. I would also venture to assert that if this draft was compared to the speed zoning recomendations of the ITE the differences would be obvious to all and a conclusion similar to mine would be easily reached by everyone. Why doesn't the NMA have a link to the ITE speed zoning recomendadtions or a page that presents the actual text of that document?
The 1996 document was a small tweak in language from the earlier version which was, as I remember, from 1993. I do not know whether it was later formally adopted, or not, but the newer version changed very little. I once had the 1993 version, but have lost it. ITE documents are available only to members, so we cannot link this.
Since I once compared the two versions in detail, I know that Mr. Mckrackin's second paragraph above is wrong, offensive in the extreme, and founded upon nothing nothing but his rants. If he makes one more idiotic unfounded accusation like this, I will stop replying. If someone else wants to then take up the challenge of dealing with offensive unfounded accusations, they would be welcome to do so.
So then why does the actual document not appear in full text on the NMA website. I have compared the wording of the NMA website with the document that was published by the ITE in Feb 2001 why does that document not appear on the webpages of the NMA? I wish you would stop responding, I also wish you'd stop Emailing me. As far as the unfounded accusations are concerned they are questions of why the NMA would post such an old unofficial version of a document that was published in 2001 and is a matter of public record in the ITE Library and the Library of Congress. There is only 1 conclusion that can be drawn from that and it isn't that the NMA is being entirely honest in it's presentation of materials.
Fine, I am done with Mr. Mckrackin. His baseless accusations have made me unwilling to reply further. If someone else wishes to deal with this nonsense, they are welcome to do so.
The only Logical conclusion is that the draft version supports the NMA's agenda while the actual ITE recomendation does not. Unless we go as far as to accuse the NMA of altering the draft to support their agenda
The question is still unanswered as to why the NMA would have a draft from 1996 posted on their website and NOT have the actual recomendations of the ITE either on their site in text or a link for readers to follow to the actual document. I find it extemely suspect that a 14 year old DRAFT version of a document is the referrence that the NMA is using to convince us that the ITE recomendations support their work. The actual document is a matter of public record as long as it is posted in it's original form would not constitute a violation of any trademark or copyright laws. One must ask the question that if the actual document is available and could be used why does the NMA Not use it.
The Question still remains unanswered on why the NMA would have a DRAFT version of a document that existed in 1996 portraying what the ITE's recomendations are. If those recomendations were put into an actual document why then isn't that document part of the NMA website? The answer is that those recomendations did not make it into an official document exactly the way the draft portrays them and the NMA can't rationalize the actual documents contents to support their agenda.
As usual with any discussion with an NMA member my position is being misrepresented. I recognize these individuals posting here as the liars that they are and that they represent an organization of liars who do not have the best interest of the people of this country at heart. They want essentially 2 things. 1) to drive faster legally. 2) to make it virtually impossible for the police to enforce the speed limits. Anyone who has an IQ above the moron level should be able to identify their use of propaganda and misrepresentations of fact. If you have been sucked into their vortec of lunacy I feel soory for you.
We should all feel sorry for Mr. Mckrackin who has to resort to personal attacks, rather than honest and civil debate with people who understand the science.
We should all feel sorry for Mr Walker who can only prevail in this issue by misrepresenting facts and data, misdirecting readers or lying about the science. That I point out his lies does not mean I am resorting to personal attacks, we both know If I personally attacked him the content would be much worse than bringing attention to the fact that he is a liar. Mr walker had a year to debate me in private conversation and I still am unconvinced his methodology will result in anything other than a more dangerous driving enviroment. Mr Walker either doesn't understand the science or he is a liar. since he claims to be a 40+year student of the science then he must be a liar.
Perfect example, for quoting the data and research, Mr. Mckrackin says I am a liar.
I understand that Mr. Mckrackin is not convinced that the Parker, ITE, SAE, 17 states, etc. methods will result in greater safety. I am convinced, but I do not call him a liar for not being convinced. I merely say I think he has reached the wrong conclusions and that his conclusions are not supported in the research. Mine are.
I believe Mr Walker is misattributing my position and narcassistically implying that only members of the NMA truly understand those works. In reality only NMA members understand the perversion of those works to achieve their goals. It is those perversions that Mr Walker so often throws out as fact that make him a liar. He is not the only NMA member I hold in that light. If Mr Walker could correctly attribute my position and accurately revisit things I have offered I may not be so quick to say he is a liar. However, I have read much of the NMA website and found many factual errors. which appear to be made for the sole purpose of strengthening the NMA's case to raise speed limits(although not all the errors were on that subject matter) When made aware of those errors Mr Walker took no action to have them corrected. That makes him an accomplice to the lie and therefore a liar.
If posting the 85th as the speed limit to correspond with most of the research over the last 70 years is a perversion – then the ITE, SAE, TRB, Parker, Cirillo, 17 states, etc are perverted – and I choose to support them.
Mr. Mckrackin gave me a list of things on the NMA website he thinks should be changed. I have REPEATEDLY told him, both here and privately, that I will take a look at them. It is not an instant priority item for me at the moment. He chooses to take the lack of instant action to make another personal attack to call me a liar. It is his right to say whatever he wants, but most readers will probably see it differently.
I gave the list of things that are on the NMA website that do not accurately represent that which they are supposedly quoted or paraphrased from. I gave him that list 4-6 months ago yet he has yet to accomplish changing any of them. If I witness the changes I will alter my opinion that Mr Walker is merely giving me lip service about making those changes.
Mr. Mckrackin's list in the email is dated 12/1/09.
At some point I will get to it, but our relations have deteriorated severely since I got the list because of his incessant unfounded rants and a really obscene private response (to which I unfortunately responded obscenely in a fit of anger). Working on the list has moved down in the priority list for me, but it is something I will look at in the future. Note I will be gone 2/28-3/17 to England.
This rant does not deserve a response, it is so far wrong that most readers will see it as just a rant, with no valid content.
If you enforce as mr Walker suggests to the top 5% you will be allowing 2/3 or 66% of the unlawful drivers to go undetected and/or unenforced. If the 85th percentile speed is the safest speed to travel at then allowing these drivers who are adding risk of crash to the traffic stream and severity of crash to the traffic stream is actually degrading the safety of all the drivers in that traffic stream and for Mr Walker to suggest that this is the SAFEST method would be a lie.
No, Mr. Mckrackin, enforcing against about the top 5% is the range where the drivers who MAY cause safety issues with their speed alone are found. Those at +1 to +4 over the 85th are NOT the unsafe drivers, their risks are infinitesimally higher than those at or just under the 85th. People who understand the science know this and want to direct our scarce enforcement resources versus those few drivers who actually can cause safety risks with their speed alone.
IF the speed limits are corrected to the safest point on the crash incidence curve ANYONE who exceeds that posted limit are drivers who may cause safety issues because of their choice of speed. EVERYONE who exceeds a corrected limit is adding risk of crash to the traffic system and adding risk of sverity of crash to the trafic system. The risk associated with drivers at 1 to 4 mph above the 85th is greater than the risk of drivers 1 to 4 mph below the 85th and we have all seen Mr walker promote those risks as dangerous enough to move the speed limit higher and closer to the 85th percentile….cont…..
If the risks at 1 to 4mph below the 85th percentile are great enough to prevent Mr Walker from considering posting the speed limit there then how is it that he would allow speeds above the 85th percentile that have greater risk of crash associated with them and greater risk of injury or death associated with them? As I have said many times I am not against correcting the limits, But I am against allowing the unlawful behavior of choosing speeds above the so called corrected(safest) speed. Mr Walker and I would actually agree if he didn't insist on allowing a majority of the unlawful behavior of exceeding the corrected limits. Think about WHO would insist on allowing this unlawful behavior above a speed limit set at the safest point on the risk curve.
I have said this many, many times, but the reason you do not post the speed limit below the 85th percentile is that artificially low limits will never be respected as real, or based on safety. See the first reply, by me, in this thread. In 19 of 37 cases I looked at, just rounding down from X3/8 or X4/9 resulted in limits below the 67th percentile – the lowest permitted level in the ITE paper. Rounding down from X2/7 or X1/6 would result in many limits at or below even the 50th percentile — a totally unacceptable result. Having made this study, I now completely reject always rounding down to obtain a posted speed limit. We must round up or down appropriately to obtain posted limits no more than 2 mph different from the 85th.
A part of the 85th percentile methodology is psychological, to set limits so that the super-majority of drivers see them as reasonable and worthy of respect. That will also mean they tend to gain respect for traffic laws in general, AND for the officers that enforce them. Limits that define too large of a percentage of drivers as violators will not achieve these goals of voluntary compliance and respect. The ITE said in their paper to not post below the 67th percentile and this matches the level of a failed bill in Congress around the time of the end of the NMSL. I believe this is a reasonable protocol to follow (except for the very small number of cases where the hazards are not visible to the average driver.)
Mr. Mckrackin is right, we would agree if I accepted his enforcement protocol to target anyone over a posted limit. I simply think that no legitimate venue would enforce at +2 or +3 over a properly rounded 85th. AND, I do not think it has any significant safety value, particularly compared with targeting the enforcement versus about the top 5% where the real dangers lie. I see no way to reconcile these views, and I see nothing in the literature to support ticketing at +2 or +3.
Mr Walker just can't correctly attribute anything I say. He incorrectly attributes things I offer in order to further his own agenda, the agenda of the NMA. The test case is already underway to see if the number on the sign can be enforced, Utah has stated that this is how they will enforce the new 80mph speed limited sections of interstate. Mr Walker cites my protocol for enforcing speed limits AFTER they have been corrected for safety by posting them to the 85th percentile speed rounded up. My enforcement protocol differs if we used the 85th percentile speed rounded down . My Protocol differs again if we the Top of pace instead of the 85th percentile speed to determine the number on the sign. Mr Walker is aware of all of those protocols but he has chosen the one that would be least popular and taken it out of context of when I would use it to make you believe I would always use this protocol, I would not. The protocol I used would be dependant upon how the number on the sign was derrived.
Utah SAYS they will enforce the 80 very closely, but people who know the numbers and understand these issues know that is absolutely impossible to do. It will be completely normal for cars to drive there at 81-84 mph with essentially zero chance of receiving a citation for speed alone.
I am now set, as shown in several posts above, to using the 85th rounded up from X3/8 or X4/9 or down from X2/7 or X1/6. (I do NOT support always rounding up.) I assume that the officer involved will NOT have the traffic investigation and speed survey data for every road in their area — and thus will not know if the posted 70 was derived from a 68/69 rounded up or a 71/72 rounded down, or a survey that ended right at 70. Even if they had the large book of surveys for all the roads in their area, the numbers float up and down slightly. A road that surveys today for 71 may well survey at 72 tomorrow and 70 the day after that. On an absolutely perfect day with very light traffic, it might be 73 and on a day with a little bit of mist, it might be 67. The numbers are NOT absolutes and this is another key reason why the cutoff for enforcement cannot be too close to what the sign says.
Given these realities, would Mr. Mckrackin please define the enforcement protocol on this Road X that is posted at 70 mph, and please be specific.
The real danger is allowing drivers who exceed a speed limit that has been set to maximize safety proceed without recognition or punishment. I understand fully the limitations of enforcement and I would adjust my enforcement strategy according to where in the risk curve the speed on the sign falls. Mr Walker would simply allow drivers upto the 98the percentile proceed as if they were compliant and just as safe as the motorists at the 85th percentile. If at speeds above the 85th percentile the risk of crash is increasing and additionally the risk of severity of crash is increasing exponentially, do you want your wife and infant child who are traveling at the 70th percentile speed exposed to traffic that is at or above the 98th percentile speed , knowing that these drivers will not be notice or have their behavior modified by enforcement?
I accept the fact that the numbers float slightly and that rounding correctly up or down means the +5 mph enforcement threshold means the enforcement really means the enforcement starts somewhere in the top 2% to 8% range of the total flow, averaging about the top 5%.
Mr. Mckrackin seems to believe that it is possible to enforce versus perhaps 10% or 15% of the total flow and achieve meaningful behavior modifications for the whole speed distribution. People who recognize the massive numbers involved on high volume roads see that this is impossible to achieve. When any one driver risks getting one low level ticket every 4 or 5 years or so — and knows the risk on any one trip is infinitesimally low, it becomes an annoying road tax issue, not a behavior modifying event. This is the reality I know to be true, but Mr. Mckrackin has other views.
First, a note about my name change. James Young was already taken on the Intense Debate site so I had to modify my screen name but be assured that I remain steadfast in my opposition to the faux academic excuses used by some to oppose progress in traffic engineering and safety. Speaking of names and phony stances, we have been plagued with the ignorant ranting of an anti-speed cabal plant with the puerile name Phil McKrackin. One can only wonder when his friends Jack Mehoff, Mike Hunt and Mysha Long will join in his ignorant diatribes.
PMc has the unfortunate habit of incorrectly parsing paragraphs, sentences and even single words to the point where he makes the original author’s argument mean something completely different. Then, of course, he attacks the straw man in classic academic dishonesty.
Caution: his stunning ignorance degrades this entire site.
You forgot my buddy Pat MaGroin. Calling me ignorant is like saying that your wife isalive and well and Mr Walker's wife isn't a terrorist.
The lower fatality rates may have ocurred while we have higher speed limits on many freeways and slightly higher travel speeds on those freeways but not as a result of those higher speed limits or higher travel speeds which is something YOU and the NMA both like to imply.
Having the correct, or more correct, posted speed limits has a positive effect and is part of the improvement, though NOT the controlling factor. What you CAN say for certain is that the higher posted limits and slightly higher actual speeds did NOT lead to the mayhem and the up to 6,400 more fatalities per year blood bath that the safety lobby predicted when the NMSL was repealed. That prediction was nonsense and known to be so by both those that said it and those who wasted the time to read such nonsense.
The New format looks good. However, the newest comment we can view is 55 weeks ago? who really cares about the content from 55-74 weeks ago. I notice that all content that I have previously posted has been removed, can you say censorship?
Old comments are being imported into the system but it's a slow process. Hopefully it will be done by the end of the day.
PMc writes as quoted out of context by Mr Young: [sic] {My Plan is to disallow the stacking of speeds that get rationalized.}
Mr Young(Whatever that means.)
Phil replies{That means that if the safest place to post the limit is near the 85th why do speeds in excess of the 95th percentile need to be allowed. Parker said that the greatest safety benefits could be gained by posting the speed limit within 5mph of the 85th. I don’t interpret this as you and Mr walker do, to say that the greatest safety is at the 85th but instead it is near the 85th. Inspection of the crash incidence curve of Solomon or later researchers show that the lowest point on the risk curve is actually below the 85th percentile. So you have rounded up the to the 85th for the safest place to post and then you round UP again so that the posted limit will be on a “5 “or “0”. Then you rationalize that an enforcement grace is necessary above the posted limit. When all your rationalizations are complete you have added upto 7 to 12 mph above the safest point on the curve as speeds you will allow.(this is a range from minimum rounding and rationalizations to maximum rounding and rationalizations)
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PMc writes as quoted out of context by Mr Young{An additional point that I was making is that if Mr Young was aquainted with Solomons work why would he tell me that Solomon’s work did not include work regarding an increases in crash severity with increasing vehicle speeds. }
Mr Young(I said no such thing. I only point out that the inclusion of that verbiage was far from the central point of his work and was essentially gratuitous. That you cannot differentiate important concepts from less important or even trivial is your own shortcoming, not dishonesty on my part.)
Phil replies{As the previous exchange from January 23, 2010 at 9:55 pm You specifically denied that Solomon’s work did not include work regarding the correlation between speed and crash severity. An important conclusion that Solomon drew was that crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.
January 23, 2010 at 9:55 pm exchange
“PMc writes as quoted out of context by Mr Young{Tell me Mr Young, Solomon(1964) included a crash curve that referenced risk of casualty crash with speed and the overal risk of crash referenced to mean speed. Why is it that you refer to the overall crash risk but never address the casualty crash risk.}
Mr Young(No, in fact David Solomon referenced no such “casualty crash curve.” He did produce a seminal work relating crash incidence as measured by deviation from mean speed, a landmark work because it gave the first academic look at traffic safety and pointed out that the claims of the safety cabal – as speeds increase, the likelihood of crashes and deaths increase (sometimes exponentially) – were false and self-serving. There is no such thing as a Solomon “casualty crash curve,” certainly not one that means injury OR fatality, thus contradicting the meaning of “casualty.” That you do not know this means that you don’t know what you’re talking about.
Could we construct a “casualty crash curve”? Yes, but it would be very vague because the risk of a fatality in a crash depends of many more variables than the speed of the vehicle immediately prior to the crash. I am far less likely to be a fatality at 70 mph in my Bimmer than at even 50 mph in a 55 Oldsmobile. Therefore, the graph would be essentially meaningless.)”
Phil continues his reply{That Solomon did not plot a graph so that it was easy for you to look at the pictures does not indicate that he did not perform the work or draw the conclusions that are clearly written in his study. The following Table appears:
Rates for All Accident Involvements and for Consequence-Specific Involvements
(from Solomon, 1964)
Speed Category Involvements Persons Injured Persons Killed
(mph) per 100 mvm per 100 mvm per 100 mvm
————————————————————————————
= 73 289 313 118
______________________________________________________}
PMc writes as quoted out of context by Mr Young{John [Carr] an NMA activist paraphrased Braceras’ comments in a light favorable to the agenda of the NMA. He specifically left out important information to portray the story as being proof of the NMA’s agenda.}
Mr Young(Carr omitted nothing and added nothing to Braceras’ or the UDOT press release. KSL (radio and television) and the Deseret News (Salt Lake Valley daily) report the same thing Carr reported.)
Phil replies{Carr Did like you do he quoted out of context omitted important data to imply that the roadways that received higher speed limits actually became safer.}
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PMc writes as quoted by Mr Young out of context{You do not consider all the science and even within the works you cite you only accept portions of the works.}
Mr Young(Not quite true. More importantly, academics must be able to ascertain the relevant and important parts of any body of work and ignore the rest. It would be impossible to include all of every work in each subsequent work and knowledge would suffer. In the case of Solomon’s alleged physics work, it was not a significant finding, nor was it even new. It was, in fact, about 300 years old. Do you evn have an idea how trivial a point that is compared to his major finding? It is as though I found a lost Rembrandt and you complain because I didn’t describe the broken frame. How dishonest you are!)
Phil replies{Not quite true? So there is truth to the statements that you purposefully ignore certain scientific works? Your justification is that you as an academic are duty bound to decide for all of the rest of us what scientific studies and what content within those studies is relevant. You tell us what conclusions to believe and what conclusions to deny and all without any bias for your own personal agenda? As far as I am aware it was new and relevant because although it was 300 year old science it had not been applied to traffic safety. Unless you are telling us that Sir Issaac Newton owned an automobile? This work was extremely relevant because it showed the relationship between speed and severity of crash Solomon’s conclusion that “crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.” Is extremely relevant to the question at hand “where is the safest place to post speed limits?” That you simply deny the relevance and the existence of the science does not mitigate it’s relevance. It may be a trivial point to you but then you want to ignore this science. It may very well be as though you found a lost Rembrandt and when I pointed out that the frame was broken and you reply “no it isn’t, this frame is like new”!}
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PMc writes as quoted out of context and incomplete{ . . .several other researchers have affirmed his conclusions and some of those have formulated such a “casualty crash curve”. That you seem clueless about it’s existence is evidence of your ignorance, untruthfulness or both.}
Mr Young(I am aware that efforts have been made to formulate a “fatality crash curve.” Note that I am using the more neutral and more exact language of NHTSA rather than PMc’s vague bizarre world terminology. The problem still obtains how do we differentiate between a crash at 50 mph that killed 4 people and one at 51 mph that resulted only in property damage? Do not get me wrong; I have no problem with the concept of creating such a curve for we might learn something valuable from it. But the practicalities of constructing a meaningful, widely-accepted curve probably preclude it as a useful tool in our arsenal.)
Phil replies{So if you are aware of the science why do you not accept it? We could differentiate between the crash at 50mph which kills 4 and the crash at 50mph that is property damage only in the same manner we differentiate between the 51mph property damage only crash and the 52mph driver who does not crash of course the resulting curve would not be able to be used by you to support your agenda because it only go up as speed increase. That you have no problem with the concept of creating such a curve is irrelevant because one already exists. I do agree that YOU could learn something from it. What this curve shows us already precludes that it will never be a tool in an NMA members arsenal. Let me just clarify why I bring this “curve” or the relationship between speed and severity of crash up. If we are measuring how safe our highways are by how many casualty crashes occur shouldn’t the incidence curve used be the one for casualty crash? If you want to use the overall crash incidence curve as the standard of where to set limits then you should measure safety by number of crashes regardless of the crash consequences
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PMc writes as quoted out of context by Mr Young{You go out of your way to disregard it. Other science you embrace very tightly unfortunately that science is only small portions within larger works and the remainder of the works don’t even seem to exist with you.}
Mr Young being clueless(??)
Phil replies{You deny the existence of the work in Solomon’s study about crash severity, you seem clueless that a casualty crash curve exists yet you claim to embrace the science. When in fact you embrace very tightly only the science that supports your agenda.
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PMc writes as quoted out of context by Mr Young{Risk of crash rises faster above the 85th than it does below the 85th as speeds deviate from the mean. It is NOT more dangerous below the the lowest risk point, it is more dangerous above it.}
Mr Young(That is just flat wrong. Look at the Solomon curve. Note how the crash incidence curves turns up as we move to the left of the minimum point. More crashes mean more risk below the speed at the minimum point (the 85th percentile). Note also how the curve turns up to the right of the 85th percentile but not nearly as steeply as below.
What you should be taking from Solomon is his methodology, his crash incidence curve shape and location; and you should be taking his application of the scientific method to traffic safety.)
Phil replies{It is not wrong and clearly anyone who looks at the curve can see that the right side rises much faster than the left side. If you doubt that pick a point on the curve below the low point and draw a horizontal line parallel to the base line and then a two vertical lines down from the intersecting points of the curve and you will see that the deviation from the low point above the low point is much lower than the deviation from the low point below the low point. This indicates that the same amount of risk occurred as a result of a smaller deviation or the risk is increasing faster above the low point. I take all of what you do from Solomon’s work plus I see the value of his conclusion that “crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.”}
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PMc writes as quoted by Mr Young out of context{Casualty in this context means a person who is injured in the crash. Note that the Property damage and injury tolls add up to the total number of crashes and that fatality crashes are a subset of the injury crashes.}
Mr Young(With all due respect, I’ve never seen anybody define “casualty” with respect to vehicle crashes as anything other than fatality, i.e, death. “Casualty” as “injury” is too vague and not in general usage, certainly not by NHTSA. You take these weird journeys down Lewis Carroll’s rabbit hole at your own risk.)
Phil replies{I explained my usage of the term “casualty crash” and how I was using it in my text. That you are ignorant of any use in relationship to vehicle crashes where it is used to describe anything other than fatalities is irrelevant I explained how it was being used in my context.}
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PMc writes as quoted by Mr Young out of context: {It doesn’t matter who Janice Fisher is or what her position on this issue is.}
Mr Young(You quoted her as though her question was a revelation of enormous magnitude but when I pointed out what a negative representative she was, all of a sudden it doesn’t matter who she is.)
Phil replies{I already knew there was a correlation between travel speed and risk of casualty crash. It is irrelevant to me who asked the question My emphasis was on the answer: That, YES, there was increased risk of injury and/or death associated with driving faster and that it is BASIC PHYSICS. When you tell us that you want speed limits set scientifically you apparently don’t mean according to the laws of PHYSICS because you totally ignore anything associated with severity of crash.}
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PMc writes as quoted by Mr Young out of context{ Does her position on this issue change the fact that it is true that we’re more likely to be killed in a crash the faster we’re going?}
Mr Young(Unsurprisingly, PMc is once again too simplistic because he ignores a lot of significant material. We economists use the phrase ceteris paribus, meaning to hold all other things the same, usually in order to isolate the effect of one phenomenon on another or as a teaching device. The only problem with this assumption is that it never holds true because the real world isn’t like that. So, too, it is with PMc’s claims. We have gone to great effort and cost, using vast resources, to mitigate the known kinetic energy at any given speed. Obviously, the KE does not change but that is less important than that we can now disperse the energy with good effectiveness. The world has changed around Solomon and PMc; Solomon would have embraced the change; PMc would rather cry that we’re out to get him.
The key element of Solomon, the thing that we must take from his landmark work is the methodology of determining the crash incidence curve because it was new and revelatory and can still be used on different roadways and different circumstances. The “revelation” that KE increases as the square of speed was essentially gratuitous, something that we had known for about 300 years.)
Phil replies{Unsurprisingly Mr Young again decides to ignore the BASIC LAWS OF PHYSICS. Solomon didn’t have the revelation that KE increases as the square of velocity, he knew that going into his study. The revelation was that when applied to motor vehicle travel it expectedly revealed that the risk of being injured or killed in a motor vehicle crash was correlated to how fast you were driving. Something you will never admit is important, but then you just want to drive faster. What is your motto? “Higher speed limits at any cost?” If the science is 300 years old why then do you ignore it?
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PMc writes as quoted out of context by Mr Young{That we design ways to decrease the amount of kinetic energy . . .is not justification to then arbitrarily increase the amount of kinetic energy present in the crash exponentially with higher speeds.}
Mr Young(Certainly it is. That is exactly why all that effort has been expended. Why else would we expend all that effort, knowledge, time and resources if we should never use it? Are you really that incognizant of the value of higher speeds translating to higher productivity?)
Phil replies{Back to your motto “higher speed limits at any cost” Certainly a vehicle that was not designed to mitigate some of the kinetic energy of a crash so that the driver is not subjected to those adverse forces would yield more injury than a vehicle that has been designed to lessen the amount of kinetic energy that an occupant is subjected to in a crash. However, A vehicle like the BMW 750i that has such safety features designed into it and is tested with a 40mph offset frontal crash test is not going to dissipate all of the kinetic energy so that the occupants are subjected to zero Kinetic energy even in a 40 mph impact. Now add more speed 70mph to the crash and there is an exponential amount of increased kinetic energy. The 75% increase in speed results in a 206% increase in kinetic energy. The vehicle could not dissipate all of the kinetic energy present at 40mph now you’ve added 206% more kinetic energy. How much of that will be transferred to the occupants inside?
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PMc writes as quoted out of context by Mr Young{This challenge is a dishonest attempt to mitigate the effects that kinetic energy has on a crash.}
Mr Young(No, it’s not. It is an attempt to get you to think outside your limited little world.)
Phil replies{In either automobile that you listed the slower the impact speed the less likely you would be to get seriously injured or killed. Only an idiot would choose the higher impact speed as safer in either car. Therefore your challenge of a slow speed in a vehicle not designed with kinetic energy absorbing technology vs a higher speed in a vehicle that utilizes kinetic energy absorbing technology is intellectually dishonest. However, in a 1955 Oldsmobile that weighs approx 3800lbs at 50mph carries. 317,033 ft/lbs of KE with it into a crash and a BMW 750i assuming a similar weight at a speed of 70mph carries 621,386 ft/lbs of kinetic energy into the crash a 40% increase in speed results in a 96% increase in kinetic energy that must be dissipated can the BMW absorb all of the kinetic energy of the 55 Oldsmobile plus a significant portion of the 304,353 ft/lbs of extra kinetic energy? The results of crashes with those vehicles at those speeds would likely be the occupants of the 55 Oldsmobile having a chance of survival while the occupants of the BMW nearly no chance of survival.}
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PMc writes as quoted out of context by Mr Young{I agree with placing speed limits at the point where the crash-incidence curve is at it’s peak low point [whatever that is]. Rounding is just another way for you to justify greater speeds.}
Mr Young(No, rounding is just a mathematical nicety to make it easier to understand.)
Phil replies{Rounding is a way of standardizing between the speedometers and the speed limit signs so we are not trying to measure a speed of 38mph with a speedometer that graduates in 5mph increments.}
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PMc writes as quoted out of context by Mr Young{ However, I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed.}
Mr Young(As Jim Walker has already astutely pointed out, that would be impractical. In fact, it is too bizarre to contemplate and impossible to implement. A bad policy is one that, among other factors, cannot be effectively implemented; your offering is a classic example of that.)
Phil replies{we will see there is a test case under way Utah is enforcing the new 80mph speed limits at zero tolerance. I however I believe it to would have negative safety consequences to post the 85th which is rounding up from the low point on the curve then round up again from the 85th to the next 5mph increment and then add 5mph for an enforcement grace. This results in 7-12mph over the safest point on the risk curve and may allows speeds in excess of the 95th percentile. If the safest place for traffic to be traveling is near the 85th why do you go to such great lengths to have speeds well above that be allowed?}
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PMc writes as quoted out of context by Mr Young{In the event that you do require an enforcement grace I would lower the speed limit by that amount(If you require a 5mph grace then find the 85th round to the next 5mph increment and subtract 5mph) so that we are not compounding errors above the 85th that may lead to unintended consequences.}
Mr Young clueless again(What in the hell does that mean?)
Phil replies{I am suggesting that if the safest place to have traffic travel is near the 85th percentile then we should post limits and allow enforcement graces that encourage that behavior and enforce strictly to deter the unwanted behaviors of exceeding that “corrected” limit and driving outside the pattern.}
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PMc writes as quoted out of context by Mr Young{So Randy and I can expect censorship efforts against us?}
Mr Young(What a bizarre response. (1) It does not follow from the discussion, (2) the NMA does not work that way, (3) I don’t want you censored because I want your silly diatribes exposed, thus making the safety cabal look conspicuously stupid.)
Phil replies{This comment was in response to your comment “Sadly, this site has suffered and that has corresponded exactly with Randy’s and your appearance here. I expect the site to recover, especially if the new formatting and sorting options can make it easier to follow.” I realize it is hard for you to remember all the crap your brain spews but try to pay attention. My responses here have nothing to do with anything or anybody in the safety cabal. Suggesting such a thing is nothing more than an attempt to associate me with them so readers will attribute me their values, which you clearly know is not the case. More of your profound intellectual dishonesty.}
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Mr Walker (One of Mr. Mckrackin’s several proposals is to correctly round (or round up) the 85th and then enforce it with essentially zero tolerance. He said ” However I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed.” This is totally impractical and would lead to a court system that clogged rapidly shut. Americans will NEVER accept tickets at +1 or +2, regardless of the method of setting the limit.)
Phil replies{We will see! Utah is enforcing the new 80mph limits at zero tolerances. Of course it wasn’t said like that but it was said that drivers should not be surprised for getting ticketed for any speed above the 80mph. Where is your ridiculous argument that we do not have enough police resources to cite that many drivers?}
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Jim Walker(Solomon’s work was primarily on surface highways with 1950s and early 1960s cars. The results today on freeways in modern cars are quite different – as indicated by the 2 to 4 times lower fatality rate on freeways today compared with surface highways, even with the higher speeds involved today.)
Phil replies{If this is true then it would be intellectually dishonest to use his curve to post freeway and interstate speed limits. The higher speeds at which we travel today, on the interstates, have no causal effect on safety. It is not safer on the interstates because we are traveling faster it is a lie to imply such a thing}
Mr Walker(Solomon’s low point on the risk curve was in the mid-60s mph, still true today in most places for surface highways. Remember the 1941 NSC report that put the 85th on rural MO highways in 1940/41 at 62.5 mph and the last NMSL report in MI in 9/95 which showed 85ths of 63-69. If you had to use one number nationwide for good rural surface highways in non mountain areas — it would be 65, the same limit that was used by MI and IN and many other states before the counter-productive NMSL entered the picture. As Mr. Mckrackin knows, I do NOT support blanket one-size-fits-all statutory limits, I support legitimate traffic investigations and speed surveys for every road. Texas has done that with rural highways and you will find surface highways posted at 45, 50, 55, 60, 65, and 70 — as they found appropriate for each individual area. Using 85th limits is almost always correct – individually measured and posted.)
Phil replies{Apples and oranges. It is intellectually dishonest to suggest that 85th percentile speed measured in Sept of 1995 in Michigan proves anything by comparing it to a different rural highway in Missouri. You pay lip service to legitimate traffic investigations, when suggested that the 85th not be the only consideration in setting speed limits you outright refuse to allow any other criteria be used like the pace speeds, crash history ect, ect. If 85th percentile speeds will almost always be correct then you should have no problem allowing the use of the other criteria to confirm that the 85th percentile is the right speed.}
Phil Mckrackin says:
January 26, 2010 at 4:51 pm
PMc writes as quoted out of context by Mr Young: [sic] {My Plan is to disallow the stacking of speeds that get rationalized.}
Mr Young(Whatever that means.)
Phil replies{That means that if the safest place to post the limit is near the 85th why do speeds in excess of the 95th percentile need to be allowed. Parker said that the greatest safety benefits could be gained by posting the speed limit within 5mph of the 85th. I don’t interpret this as you and Mr walker do, to say that the greatest safety is at the 85th but instead it is near the 85th. Inspection of the crash incidence curve of Solomon or later researchers show that the lowest point on the risk curve is actually below the 85th percentile. So you have rounded up the to the 85th for the safest place to post and then you round UP again so that the posted limit will be on a “5 “or “0”. Then you rationalize that an enforcement grace is necessary above the posted limit. When all your rationalizations are complete you have added upto 7 to 12 mph above the safest point on the curve as speeds you will allow.(this is a range from minimum rounding and rationalizations to maximum rounding and rationalizations)
JCW 1/26 My stance is to correctly round up or down from the 85th and enforce at +5, which yields a MAXIMUM of 7 mph above the 85th. 80% of the time, the allowance will be 3 to 6 mph above the 85th. On the 85th being the safest place to post the limit itself, that was proven by Parker who found the lowest crash rate with 85th limits. Mr. Mckrackin consistently ignores this fact.
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PMc writes as quoted out of context by Mr Young{An additional point that I was making is that if Mr Young was aquainted with Solomons work why would he tell me that Solomon’s work did not include work regarding an increases in crash severity with increasing vehicle speeds. }
Mr Young(I said no such thing. I only point out that the inclusion of that verbiage was far from the central point of his work and was essentially gratuitous. That you cannot differentiate important concepts from less important or even trivial is your own shortcoming, not dishonesty on my part.)
Phil replies{As the previous exchange from January 23, 2010 at 9:55 pm You specifically denied that Solomon’s work did not include work regarding the correlation between speed and crash severity. An important conclusion that Solomon drew was that crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.
January 23, 2010 at 9:55 pm exchange
“PMc writes as quoted out of context by Mr Young{Tell me Mr Young, Solomon(1964) included a crash curve that referenced risk of casualty crash with speed and the overal risk of crash referenced to mean speed. Why is it that you refer to the overall crash risk but never address the casualty crash risk.}
Mr Young(No, in fact David Solomon referenced no such “casualty crash curve.” He did produce a seminal work relating crash incidence as measured by deviation from mean speed, a landmark work because it gave the first academic look at traffic safety and pointed out that the claims of the safety cabal – as speeds increase, the likelihood of crashes and deaths increase (sometimes exponentially) – were false and self-serving. There is no such thing as a Solomon “casualty crash curve,” certainly not one that means injury OR fatality, thus contradicting the meaning of “casualty.” That you do not know this means that you don’t know what you’re talking about.
Could we construct a “casualty crash curve”? Yes, but it would be very vague because the risk of a fatality in a crash depends of many more variables than the speed of the vehicle immediately prior to the crash. I am far less likely to be a fatality at 70 mph in my Bimmer than at even 50 mph in a 55 Oldsmobile. Therefore, the graph would be essentially meaningless.)”
Phil continues his reply{That Solomon did not plot a graph so that it was easy for you to look at the pictures does not indicate that he did not perform the work or draw the conclusions that are clearly written in his study. The following Table appears:
Rates for All Accident Involvements and for Consequence-Specific Involvements
(from Solomon, 1964)
Speed Category Involvements Persons Injured Persons Killed
(mph) per 100 mvm per 100 mvm per 100 mvm
————————————————————————————
= 73 289 313 118
______________________________________________________}
PMc writes as quoted out of context by Mr Young{John [Carr] an NMA activist paraphrased Braceras’ comments in a light favorable to the agenda of the NMA. He specifically left out important information to portray the story as being proof of the NMA’s agenda.}
Mr Young(Carr omitted nothing and added nothing to Braceras’ or the UDOT press release. KSL (radio and television) and the Deseret News (Salt Lake Valley daily) report the same thing Carr reported.)
Phil replies{Carr Did like you do he quoted out of context omitted important data to imply that the roadways that received higher speed limits actually became safer.}
JCW 1/26 Since most posted limits are under-posted and over-posted limits are rare to the point of almost non-existence, most will be safer when raised.
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PMc writes as quoted by Mr Young out of context{You do not consider all the science and even within the works you cite you only accept portions of the works.}
Mr Young(Not quite true. More importantly, academics must be able to ascertain the relevant and important parts of any body of work and ignore the rest. It would be impossible to include all of every work in each subsequent work and knowledge would suffer. In the case of Solomon’s alleged physics work, it was not a significant finding, nor was it even new. It was, in fact, about 300 years old. Do you evn have an idea how trivial a point that is compared to his major finding? It is as though I found a lost Rembrandt and you complain because I didn’t describe the broken frame. How dishonest you are!)
Phil replies{Not quite true? So there is truth to the statements that you purposefully ignore certain scientific works? Your justification is that you as an academic are duty bound to decide for all of the rest of us what scientific studies and what content within those studies is relevant. You tell us what conclusions to believe and what conclusions to deny and all without any bias for your own personal agenda? As far as I am aware it was new and relevant because although it was 300 year old science it had not been applied to traffic safety. Unless you are telling us that Sir Issaac Newton owned an automobile? This work was extremely relevant because it showed the relationship between speed and severity of crash Solomon’s conclusion that “crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.” Is extremely relevant to the question at hand “where is the safest place to post speed limits?” That you simply deny the relevance and the existence of the science does not mitigate it’s relevance. It may be a trivial point to you but then you want to ignore this science. It may very well be as though you found a lost Rembrandt and when I pointed out that the frame was broken and you reply “no it isn’t, this frame is like new”!}
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PMc writes as quoted out of context and incomplete{ . . .several other researchers have affirmed his conclusions and some of those have formulated such a “casualty crash curve”. That you seem clueless about it’s existence is evidence of your ignorance, untruthfulness or both.}
Mr Young(I am aware that efforts have been made to formulate a “fatality crash curve.” Note that I am using the more neutral and more exact language of NHTSA rather than PMc’s vague bizarre world terminology. The problem still obtains how do we differentiate between a crash at 50 mph that killed 4 people and one at 51 mph that resulted only in property damage? Do not get me wrong; I have no problem with the concept of creating such a curve for we might learn something valuable from it. But the practicalities of constructing a meaningful, widely-accepted curve probably preclude it as a useful tool in our arsenal.)
Phil replies{So if you are aware of the science why do you not accept it? We could differentiate between the crash at 50mph which kills 4 and the crash at 50mph that is property damage only in the same manner we differentiate between the 51mph property damage only crash and the 52mph driver who does not crash of course the resulting curve would not be able to be used by you to support your agenda because it only go up as speed increase. That you have no problem with the concept of creating such a curve is irrelevant because one already exists. I do agree that YOU could learn something from it. What this curve shows us already precludes that it will never be a tool in an NMA members arsenal. Let me just clarify why I bring this “curve” or the relationship between speed and severity of crash up. If we are measuring how safe our highways are by how many casualty crashes occur shouldn’t the incidence curve used be the one for casualty crash? If you want to use the overall crash incidence curve as the standard of where to set limits then you should measure safety by number of crashes regardless of the crash consequences
JCW 1/26 Safety is the combination of the crash risk times the severity. A crash that did not occur has no severity factor.
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PMc writes as quoted out of context by Mr Young{You go out of your way to disregard it. Other science you embrace very tightly unfortunately that science is only small portions within larger works and the remainder of the works don’t even seem to exist with you.}
Mr Young being clueless(??)
Phil replies{You deny the existence of the work in Solomon’s study about crash severity, you seem clueless that a casualty crash curve exists yet you claim to embrace the science. When in fact you embrace very tightly only the science that supports your agenda.
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PMc writes as quoted out of context by Mr Young{Risk of crash rises faster above the 85th than it does below the 85th as speeds deviate from the mean. It is NOT more dangerous below the the lowest risk point, it is more dangerous above it.}
Mr Young(That is just flat wrong. Look at the Solomon curve. Note how the crash incidence curves turns up as we move to the left of the minimum point. More crashes mean more risk below the speed at the minimum point (the 85th percentile). Note also how the curve turns up to the right of the 85th percentile but not nearly as steeply as below.
What you should be taking from Solomon is his methodology, his crash incidence curve shape and location; and you should be taking his application of the scientific method to traffic safety.)
Phil replies{It is not wrong and clearly anyone who looks at the curve can see that the right side rises much faster than the left side. If you doubt that pick a point on the curve below the low point and draw a horizontal line parallel to the base line and then a two vertical lines down from the intersecting points of the curve and you will see that the deviation from the low point above the low point is much lower than the deviation from the low point below the low point. This indicates that the same amount of risk occurred as a result of a smaller deviation or the risk is increasing faster above the low point. I take all of what you do from Solomon’s work plus I see the value of his conclusion that “crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.”}
JCW 1/26 Remember, Solomon was dealing with surface highways and I would agree that speeds much above 70 are riskier on most surface highways in most states. The risk curve for freeways has a MUCH flatter area near the bottom and rises VERY slowly for quite awhile after the lowest point.
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PMc writes as quoted by Mr Young out of context{Casualty in this context means a person who is injured in the crash. Note that the Property damage and injury tolls add up to the total number of crashes and that fatality crashes are a subset of the injury crashes.}
Mr Young(With all due respect, I’ve never seen anybody define “casualty” with respect to vehicle crashes as anything other than fatality, i.e, death. “Casualty” as “injury” is too vague and not in general usage, certainly not by NHTSA. You take these weird journeys down Lewis Carroll’s rabbit hole at your own risk.)
Phil replies{I explained my usage of the term “casualty crash” and how I was using it in my text. That you are ignorant of any use in relationship to vehicle crashes where it is used to describe anything other than fatalities is irrelevant I explained how it was being used in my context.}
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PMc writes as quoted by Mr Young out of context: {It doesn’t matter who Janice Fisher is or what her position on this issue is.}
Mr Young(You quoted her as though her question was a revelation of enormous magnitude but when I pointed out what a negative representative she was, all of a sudden it doesn’t matter who she is.)
Phil replies{I already knew there was a correlation between travel speed and risk of casualty crash. It is irrelevant to me who asked the question My emphasis was on the answer: That, YES, there was increased risk of injury and/or death associated with driving faster and that it is BASIC PHYSICS. When you tell us that you want speed limits set scientifically you apparently don’t mean according to the laws of PHYSICS because you totally ignore anything associated with severity of crash.}
JCW 1/26 Mr. Mckrackin consistently ignores the fact that posted limits have almost no effect on actual travel speeds. You have to START from that point and then decide how to set limits, knowing they have almost no effect on speeds.
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PMc writes as quoted by Mr Young out of context{ Does her position on this issue change the fact that it is true that we’re more likely to be killed in a crash the faster we’re going?}
Mr Young(Unsurprisingly, PMc is once again too simplistic because he ignores a lot of significant material. We economists use the phrase ceteris paribus, meaning to hold all other things the same, usually in order to isolate the effect of one phenomenon on another or as a teaching device. The only problem with this assumption is that it never holds true because the real world isn’t like that. So, too, it is with PMc’s claims. We have gone to great effort and cost, using vast resources, to mitigate the known kinetic energy at any given speed. Obviously, the KE does not change but that is less important than that we can now disperse the energy with good effectiveness. The world has changed around Solomon and PMc; Solomon would have embraced the change; PMc would rather cry that we’re out to get him.
The key element of Solomon, the thing that we must take from his landmark work is the methodology of determining the crash incidence curve because it was new and revelatory and can still be used on different roadways and different circumstances. The “revelation” that KE increases as the square of speed was essentially gratuitous, something that we had known for about 300 years.)
Phil replies{Unsurprisingly Mr Young again decides to ignore the BASIC LAWS OF PHYSICS. Solomon didn’t have the revelation that KE increases as the square of velocity, he knew that going into his study. The revelation was that when applied to motor vehicle travel it expectedly revealed that the risk of being injured or killed in a motor vehicle crash was correlated to how fast you were driving. Something you will never admit is important, but then you just want to drive faster. What is your motto? “Higher speed limits at any cost?” If the science is 300 years old why then do you ignore it?
JCW 1/26 Since artificially low posted limits, even those set as high as the 50th percentile, do NOT change the overall speed distribution enough to matter – trying to use the physics argument is utterly useless. We get this, Mr. Mckrackin doesn’t (or says he doesn’t).
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PMc writes as quoted out of context by Mr Young{That we design ways to decrease the amount of kinetic energy . . .is not justification to then arbitrarily increase the amount of kinetic energy present in the crash exponentially with higher speeds.}
Mr Young(Certainly it is. That is exactly why all that effort has been expended. Why else would we expend all that effort, knowledge, time and resources if we should never use it? Are you really that incognizant of the value of higher speeds translating to higher productivity?)
Phil replies{Back to your motto “higher speed limits at any cost” Certainly a vehicle that was not designed to mitigate some of the kinetic energy of a crash so that the driver is not subjected to those adverse forces would yield more injury than a vehicle that has been designed to lessen the amount of kinetic energy that an occupant is subjected to in a crash. However, A vehicle like the BMW 750i that has such safety features designed into it and is tested with a 40mph offset frontal crash test is not going to dissipate all of the kinetic energy so that the occupants are subjected to zero Kinetic energy even in a 40 mph impact. Now add more speed 70mph to the crash and there is an exponential amount of increased kinetic energy. The 75% increase in speed results in a 206% increase in kinetic energy. The vehicle could not dissipate all of the kinetic energy present at 40mph now you’ve added 206% more kinetic energy. How much of that will be transferred to the occupants inside?
JCW 1/26 Irrelevant since posted limits have almost no effect on travel speeds.
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PMc writes as quoted out of context by Mr Young{This challenge is a dishonest attempt to mitigate the effects that kinetic energy has on a crash.}
Mr Young(No, it’s not. It is an attempt to get you to think outside your limited little world.)
Phil replies{In either automobile that you listed the slower the impact speed the less likely you would be to get seriously injured or killed. Only an idiot would choose the higher impact speed as safer in either car. Therefore your challenge of a slow speed in a vehicle not designed with kinetic energy absorbing technology vs a higher speed in a vehicle that utilizes kinetic energy absorbing technology is intellectually dishonest. However, in a 1955 Oldsmobile that weighs approx 3800lbs at 50mph carries. 317,033 ft/lbs of KE with it into a crash and a BMW 750i assuming a similar weight at a speed of 70mph carries 621,386 ft/lbs of kinetic energy into the crash a 40% increase in speed results in a 96% increase in kinetic energy that must be dissipated can the BMW absorb all of the kinetic energy of the 55 Oldsmobile plus a significant portion of the 304,353 ft/lbs of extra kinetic energy? The results of crashes with those vehicles at those speeds would likely be the occupants of the 55 Oldsmobile having a chance of survival while the occupants of the BMW nearly no chance of survival.}
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PMc writes as quoted out of context by Mr Young{I agree with placing speed limits at the point where the crash-incidence curve is at it’s peak low point [whatever that is]. Rounding is just another way for you to justify greater speeds.}
Mr Young(No, rounding is just a mathematical nicety to make it easier to understand.)
Phil replies{Rounding is a way of standardizing between the speedometers and the speed limit signs so we are not trying to measure a speed of 38mph with a speedometer that graduates in 5mph increments.}
JCW 1/26 Rounding is a federal requirement which has nothing to do with how speedos read. Limits must end in 5 or 0 to be legal – a quite simple fact.
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PMc writes as quoted out of context by Mr Young{ However, I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed.}
Mr Young(As Jim Walker has already astutely pointed out, that would be impractical. In fact, it is too bizarre to contemplate and impossible to implement. A bad policy is one that, among other factors, cannot be effectively implemented; your offering is a classic example of that.)
Phil replies{we will see there is a test case under way Utah is enforcing the new 80mph speed limits at zero tolerance. I however I believe it to would have negative safety consequences to post the 85th which is rounding up from the low point on the curve then round up again from the 85th to the next 5mph increment and then add 5mph for an enforcement grace. This results in 7-12mph over the safest point on the risk curve and may allows speeds in excess of the 95th percentile. If the safest place for traffic to be traveling is near the 85th why do you go to such great lengths to have speeds well above that be allowed?}
JCW 1/26 Utah SAYS it will enforce with zero tolerance, but the numbers on high volume roads make that utterly impossible to do. My view is round up OR down, not always up – so the MAXIMUM grace is 7 mph if you enforce at +5 and 80% of the time the effective grace is 3 to 6 mph. Mr. Mckrackin makes this exaggeration over and over and over, but it is not true.
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PMc writes as quoted out of context by Mr Young{In the event that you do require an enforcement grace I would lower the speed limit by that amount(If you require a 5mph grace then find the 85th round to the next 5mph increment and subtract 5mph) so that we are not compounding errors above the 85th that may lead to unintended consequences.}
Mr Young clueless again(What in the hell does that mean?)
Phil replies{I am suggesting that if the safest place to have traffic travel is near the 85th percentile then we should post limits and allow enforcement graces that encourage that behavior and enforce strictly to deter the unwanted behaviors of exceeding that “corrected” limit and driving outside the pattern.}
JCW 1/26 Mr. Mckrackin falsely thinks we have the resources to effectively enforce versus about the top 10% of the flow as measured on a speed study. On high volume roads, this is total nonsense – you will be trying to enforce versus perhaps 20% of the total flow. Try that on a road with 1000 cars per hour with perhaps 200 in the target pool. One officer can stop a maximum of 5 per hour. The numbers make Mr. Mckrackin’s plan totally unworkable – we don’t have the resources and it would create chaos if we did.
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PMc writes as quoted out of context by Mr Young{So Randy and I can expect censorship efforts against us?}
Mr Young(What a bizarre response. (1) It does not follow from the discussion, (2) the NMA does not work that way, (3) I don’t want you censored because I want your silly diatribes exposed, thus making the safety cabal look conspicuously stupid.)
Phil replies{This comment was in response to your comment “Sadly, this site has suffered and that has corresponded exactly with Randy’s and your appearance here. I expect the site to recover, especially if the new formatting and sorting options can make it easier to follow.” I realize it is hard for you to remember all the crap your brain spews but try to pay attention. My responses here have nothing to do with anything or anybody in the safety cabal. Suggesting such a thing is nothing more than an attempt to associate me with them so readers will attribute me their values, which you clearly know is not the case. More of your profound intellectual dishonesty.}
JCW 1/26 Mr. Mckrackin’s responses and ideas closely match many of those from the safety cabal and it is easy for us to see that.
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Mr Walker (One of Mr. Mckrackin’s several proposals is to correctly round (or round up) the 85th and then enforce it with essentially zero tolerance. He said ” However I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed.” This is totally impractical and would lead to a court system that clogged rapidly shut. Americans will NEVER accept tickets at +1 or +2, regardless of the method of setting the limit.)
Phil replies{We will see! Utah is enforcing the new 80mph limits at zero tolerances. Of course it wasn’t said like that but it was said that drivers should not be surprised for getting ticketed for any speed above the 80mph. Where is your ridiculous argument that we do not have enough police resources to cite that many drivers?}
JCW 1/26 Utah SAYS it will enforce with zero tolerance, but the numbers make that impossible to do with any significant portion of the traffic flow. It becomes just another ridiculous threat they cannot carry out. If they ticket at 81 or 82 or 83, any one driver on that road may get one ticket every 4 or 5 years and the behavior modification from that risk will closely resemble zero change.
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Jim Walker(Solomon’s work was primarily on surface highways with 1950s and early 1960s cars. The results today on freeways in modern cars are quite different – as indicated by the 2 to 4 times lower fatality rate on freeways today compared with surface highways, even with the higher speeds involved today.)
Phil replies{If this is true then it would be intellectually dishonest to use his curve to post freeway and interstate speed limits. The higher speeds at which we travel today, on the interstates, have no causal effect on safety. It is not safer on the interstates because we are traveling faster it is a lie to imply such a thing}
Mr Walker(Solomon’s low point on the risk curve was in the mid-60s mph, still true today in most places for surface highways. Remember the 1941 NSC report that put the 85th on rural MO highways in 1940/41 at 62.5 mph and the last NMSL report in MI in 9/95 which showed 85ths of 63-69. If you had to use one number nationwide for good rural surface highways in non mountain areas — it would be 65, the same limit that was used by MI and IN and many other states before the counter-productive NMSL entered the picture. As Mr. Mckrackin knows, I do NOT support blanket one-size-fits-all statutory limits, I support legitimate traffic investigations and speed surveys for every road. Texas has done that with rural highways and you will find surface highways posted at 45, 50, 55, 60, 65, and 70 — as they found appropriate for each individual area. Using 85th limits is almost always correct – individually measured and posted.)
Phil replies{Apples and oranges. It is intellectually dishonest to suggest that 85th percentile speed measured in Sept of 1995 in Michigan proves anything by comparing it to a different rural highway in Missouri. You pay lip service to legitimate traffic investigations, when suggested that the 85th not be the only consideration in setting speed limits you outright refuse to allow any other criteria be used like the pace speeds, crash history ect, ect. If 85th percentile speeds will almost always be correct then you should have no problem allowing the use of the other criteria to confirm that the 85th percentile is the right speed.}
JCW 1/26 Mr. Mckrackin refuses to realize or admit that rural surface highways in many states are very similar in character and engineering design criteria. It is WHY the speeds are in such a narrow range, even across 50+ years and many states. I ALWAYS say that crash history should be a part of any traffic investigation and any suggestion otherwise is a deliberate lie on Mr. Mckrackin’s part. This was a very commonly repeated point in our year long private exchanges. The 85th and top of pace speeds are almost always within +/- 1 mph or 2 at the outside. I care not which is used to set limits – the numbers on the signs will almost always be the same. I prefer using the 85th because it is a known parameter and I choose not to lose another decade teaching politicians what “pace” means. I DO explain both to people today when in a discussion (the pace data was left off the blog entry for space reasons, not for censorship).
If you read the media articles attached to that Utah editorial you’ll see where a politician asked a question of John Braceras, Deputy Director of the Utah DOT
The question was:
Janice Fisher, D-West Valley City,
“Is it true that we’re more likely to get killed in a crash the faster we’re going?” she asked Braceras.
“It’s simple physics,” Braceras said. “Yes.”
Apparently the laws of physics have not been suspended as they have been in Mr Youngs world. Even the Deputy Director of the Utah DOT realizes that Sir Issaac Newton is relevant to this discussion.
Maybe if you dropped the narcassistic attitude Mr Young we’d get along better since I am not actually against what you are trying to accomplish. Or we can continue to exchange witty banter and fill these pages with crap, so much crap that the message you are trying to make known will be lost amongst the crap than no one will be reading soon, if they already haven’t stopped reading.
PMc writes: [sic] {If you read the media articles attached to that Utah editorial you’ll see where a politician asked a question of John Braceras, Deputy Director of the Utah DOT. The question was: Janice Fisher, D-West Valley City, “Is it true that we’re more likely to get killed in a crash the faster we’re going?” she asked Braceras.
“It’s simple physics,” Braceras said. “Yes.”
Apparently the laws of physics have not been suspended as they have been in Mr Youngs world. Even the Deputy Director of the Utah DOT realizes that Sir Issaac Newton is relevant to this discussion.}
And if you knew who Janice Fisher is, you would cautious about using her opinion on anything. She is a well-known flake, poorly educated (LDS business school) and married to an insurance broker. Her question was obviously designed to elicit a particular response because it plays to her audience well; unfortunately for the purpose of illuminating an important public policy, it is too simplistic to be of any use.
Correction: Deputy Director of Utah DOT is Carlos Braceras, not John as I originally wrote.
You and the other apologists for the safety cabal are fond of the puerile trick of invoking physics, the adult equivalent of the 6th grade debater who insists on defining god before even examining any other question.
The physics are not in question here. We accept the physics because there is good reason to accept the physics. However, what you continue to ignore is that engineers and policy makers have worked for about 60 years to mitigate physical effects during crashes, not to mention the ability to avoid crashes in the first place. Civil engineers have added multiple lanes, medians and barriers, rumble-strips, breakaway signage, crumple barriers around fixed objects, collapsible guardrails, reflective paints, etc. Vehicle engineers have added seatbelts, airbags, crumple zones, steel-belted radial tires, disc brakes, glass that crumbles, power steering and brakes, better lighting, better wipers, and collapsible steering columns, and have removed sharp objects and control in the passenger compartment. I reiterate my challenge: would you rather crash into a barriered concrete bridge pier at 70 mph in a BMW 750 or into an unbarriered concrete bridge pier 50 mph in a 1955 Oldsmobile?
Important sidebar: The reason engineers have made such effort is because speeding up traffic has the positive value of improving productivity. This is why we have jets instead of trains or stagecoaches. The NMSL cost us an estimated trillion dollars during its lifetime and one cannot even begin to imagine the loss to our economy and our lives if speeds were kept to roughly half of what they are currently.
{Maybe if you dropped the narcassistic attitude Mr Young we’d get along better since I am not actually against what you are trying to accomplish. Or we can continue to exchange witty banter and fill these pages with crap, so much crap that the message you are trying to make known will be lost amongst the crap than no one will be reading soon, if they already haven’t stopped reading.}
First, an exchange of wit requires at least two parties; you’re not holding up your end of the deal. Another term for narcissism is self-preservation and I gladly accept that as a descriptor.
You have made the claim that you support the same things that the NMA and I do but then you go way out of your way to make exceptions and place restrictions. Simple question: Do you support placing the speed limit at the point where the crash-incidence curve minimizes, rounded to the next 5 mph increment?
Sadly, this site has suffered and that has corresponded exactly with Randy’s and your appearance here. I expect the site to recover, especially if the new formatting and sorting options can make it easier to follow.
Just to make my goals very clear:
1. I want to minimize the three key rates measuring traffic safety: the crash-, injury- and fatality rates, each per 100,000,000 VMT.
2. I support setting speed limits at the point where the crash-incidence curve minimizes, rounded to the next higher 5 mph increment
3. I support the use of law enforcement resources to concentrate on the most dangerous driving behavior on the roadway. This means moving from the easy identification and stopping of “speeders” to much more difficult identification of inattentive or impaired drivers.
4. I support those laws intended to keep traffic flowing rather than restricting it in keeping with the fundamental purpose of roads and highways in the first place.
5. Individual freedom is important and using traffic laws to excuse an intrusion into individual liberties is anathema to the idea of America. “Freedom is dangerous. You can either accept the risks that come with it or eventually lose it all step-by-step. Each step will be justified by its proponents as a minor inconvenience that will help make us all ‘safer.’ Personally, I’d rather have a slightly more dangerous world that respects freedom more.” – The Speed Criminal.
6. Traffic enforcement has become a money-maker for many jurisdictions, more and more of whom openly admit it now. This is fraud and must be stopped. I support the payment of all traffic fines, court costs, extra fees, administrative fees, any cash transfers from the motorist go to a public corporation at the state level, this money then used to fund scholarships at state universities. This would immediately end all enforcement for profit and restore credibility to law enforcement as an institution.
7. Any law passed must pass the test of efficacy. That is, it must actually do what its proponents claimed it would do; failure would mean immediate and automatic rescission.
PMc writes: [sic] { If John Braceras, Deputy Director of the Utah DOT, was the original author why was the article attributed to John Carr, NMA Activist?}
John Carr wrote the article for NMA. Braceras was the spokesman for UDOT who said what Carr paraphrased.
Your first and third paragraphs are beyond comprehension and I make no comment on them.
{John Carr assigned that Accidents did not change significantly to the number of increased crashes and then witheld the data regarding the crashes in an attempt to support his agenda, so my assigning malevolence was anything but arbitrary.}
The phrase “ . . .did not change significantly to the number of increased crashes . . .” is meaningless. What I think you meant to say was that crashes did not change significantly from prior years when the 80 mph rule was not yet in effect. What you wrote is wrong and then you compound your error by saying that Carr, who merely summarized what the original author said, was sinister in his intent, yet you have no way to knowing this and one cannot reasonably assign such intent.
{It has been a while since I read Solomon(1964) but I clearly recall his conclusion about Day/night Accident Involvement Rate by Variation from Average Speed and his conclusions about day/night Accident Involvement Rates by Travel Speed. The issue still remains that you do not accept the science regarding the CASUALTY CRASH CURVE.} [emphasis added by JY]
Solomon did not formulate a casualty crash curve. He created a crash incidence curve based on the relative dispersion around deviations from the mean, a very valuable piece of work. The distinction is critical and you’re just wrong to add assertions that he did not make. You then compound this by defining a “casualty crash curve” as crashes resulting in injuries or fatalities. This is wrong. A casualty is a fatality; injuries are a separate measurement completely.
{ Solomons work did not prove, as speeds increase, the likelihood of crashes and deaths increase (sometimes exponentially), were false and self-serving. Because, with regards to speeds above the 85th percentile speed that is exactly what his work proves.}
Even more important is the fact that his curve is not a true U-shape but elongated vertically toward the deviations below the mean, more like a slanted reverse-J. What this means is that it is more dangerous to be well below the minimum point than it is to be slightly above it. Of course, most drivers perform this calculus internally and we call that risk homeostasis. The only problem with driving in strict accordance with that internal calculus is that the safest point is usually illegal.
{ . . .Solomon concluded that crash severity increased rapidly at speeds in excess of 60 mph, and the probability of fatal injuries increased sharply above 70 mph.”}
What you omit is very important. What is most important about Solomon’s work is the construction of curve and the relationship of the curve as it diverges from the minimum point. While that still obtains, his work (conducted in the 1950s and early 1960s) is now 50 years old and conditions have changed. Because of the intervention of civil and mechanical engineers (and others), we are able to reduce the likelihood of fatal injuries at even high speeds, not to mention avoiding crashes in the first place.
{ A casualty crash curve does exist in at least 3 other works . . .}
A distribution of fatality crashes exists now but we must be very careful in their use because so many factors could and do change. Were all the vehicles 2010 Volvos or 1960 Chevys? Was the pavement wet? How many were suicides?
{Readers should question why you deny that this science exists when it obviously does and If you want speed limits set scientifically why would you ignore such an important portion of the science on where the safest place to post them is?}
No, the real question is why do you keep claiming that I deny the science when I embraced it well before you ever came onto the scene? I just am unwilling to claim that the science says something that the original researchers did not say.
{ It is not meaningless IF SAFETY IS THE GOAL. But then safety has never been your goal or the NMA’s goal. 33.6% of traffic crashes in 1999 were casualty crashes, 33% in 2000 were casualty crashes why then do you use casualty crashes as a measure of safety yet not use the applicable curve to choose the safest speed to post on the sign?}
First, why don’t you let me decide what my own goals are? I have outlined them clearly in a prior post. Next, according to NHTSA in 2000, we had approximately 6,356,000 crashes, of which 37,526 were fatality crashes; that is 0.59% of crashes. Your 33% is absurd and that is why no nobody here takes you seriously.
I understand you have a need to exclude Physics because including it would change what is reasonable and safe.
It doesn’t matter who Janice Fisher is or what her position on this issue is. Her position may have led her to ask the question of “Is it true that we’re more likely to get killed in a crash the faster we’re going?” However HER position on the issue did not dicatate the answer that the director of Utah DOT gave, which was a truthful yes. Does her position on this issue change the fact that it is true that we’re more likely to be killed in a crash the faster we’re going? Her question whether designed or not could only be answered truthfully one way and that one way is that we are more likely to be killed in a crash the faster we’re going. Solomon studied this in (1964) and concluded that crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph.
Unfortunately I don’t accept the added kinetic energy that increased speed brings into a crash as lightly as you do. That we design ways to decrease the amount of kinetic energy that an occupant must directly experience with the use of crumple zones, collaspable steering and other kinetic energy difussing technology, is not justification to then arbitrarily increase the amount of kinetic energy present in the crash exponentially with higher speeds.
James Young(challenge: would you rather crash into a barriered concrete bridge pier at 70 mph in a BMW 750 or into an unbarriered concrete bridge pier 50 mph in a 1955 Oldsmobile?)
This challenge is a dishonest attempt to mitigate the effects that kinetic energy has on a crash. A correct comparison between the two should be would you prefer to crash into a concrete pier in a BMW 750i at 70mph or at 50mph. The BMW 750i has many kinetic energy difussing features that a 1955 Oldsmobile does not. Since most cars have those features today an honest comparison would be between 2 similar cars. Anyone who would choose the 70mph over the 50mph in simialr vehicles is an idiot. Even in your dishonest comparison the 50mph would have substantially less kinetic energy and If you had read Solomon(1964) you’d know that he concluded that crash severity increased rapidly at speeds in excess of 60mph, and the probability of fatal injuries increased sharply above 70mph. and the smart choice would be the lesser kinetic energy, especially since those kinetic energy difussing features in the BMW 750i are not tested at 70mph.
I agree with placing speed limits at the point where the crash-incidence curve is at it’s peak low point Rounding is just another way for you to justify greater speeds. However I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed. I know that you, the NMA and Mr Walker would never make such a concession. Why wouldn’t you make that concession, because you want to still justify higher speeds than the posted limit placed at the lowest point on the crash incident curve +5mph. In the event that you do require an enforcement grace I would lower the speed limit by that amount(If you require a 5mph grace then find the 85th round to the next 5mph incremment and subtract 5mph) so that we are not compounding errors above the 85th that may lead to unintended consequences. Anyone who is truly working for safety would see nothing wrong with this proposal. However if your motivations are other than safety you’ll reject it so that you can rationalize allowing much higher speeds.
Mr Young(Sadly, this site has suffered and that has corresponded exactly with Randy’s and your appearance here. I expect the site to recover, especially if the new formatting and sorting options can make it easier to follow.)
So Randy and I can expect censorship efforts against us?
Mr Young((John Carr wrote the article for NMA. Braceras was the spokesman for UDOT who said what Carr paraphrased.))
exactly my point Mr Young, John car an NMA activist paraphrased Braceras’ comments in a light favorable to the agenda of the NMA. He specifically left out important information to portray the story as being proof of the NMA’s agenda.
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Mr Young(No, the real question is why do you keep claiming that I deny the science when I embraced it well before you ever came onto the scene? I just am unwilling to claim that the science says something that the original researchers did not say.)
Your interpretation of the science is completely biased to suggest overwhelming support for your agenda. However, You do not consider all the science and even within the works you cite you only accept portions of the works. You are manipulating the science to prove your preconcieved conclusions. Did you know that Parker wrote right in his work that NOT all roads were appropriate for posting to the 85th percentile speed and that his work should not be used to rationalize increasing all speed limits? I doubt it otherwise how do you explain that you are using his work to rationalize just that?
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Phil{It has been a while since I read Solomon(1964) but I clearly recall his conclusion about Day/night Accident Involvement Rate by Variation from Average Speed and his conclusions about day/night Accident Involvement Rates by Travel Speed. The issue still remains that you do not accept the science regarding the CASUALTY CRASH CURVE.} [emphasis added by JY]
Mr Young(Solomon did not formulate a casualty crash curve. He created a crash incidence curve based on the relative dispersion around deviations from the mean, a very valuable piece of work. The distinction is critical and you’re just wrong to add assertions that he did not make. You then compound this by defining a “casualty crash curve” as crashes resulting in injuries or fatalities. This is wrong. A casualty is a fatality; injuries are a separate measurement completely.)
The relationship between travel speed and the severity of injuries sustained in a crash was examined by Solomon (1964), who reported an increase in crash severity with increasing vehicle speeds on rural roads. From an analysis of 10,000 crashes, Solomon concluded that crash severity increased rapidly at speeds in excess of 60 mph, and the probability of fatal injuries increased sharply above 70 mph. Obviously work of his that you are used to ignoring. When I wrote”The issue still remains that you do not accept the science regarding the CASUALTY CRASH CURVE.” To which you added the emphasis was to point out that even though Solomon did work in this field and did not formulate a “casualty crash curve” several other researchers have affirmed his conclusions and some of those have formulated such a “casualty crash curve”. That you seem clueless about it’s existence is evidence of your ignorance, untruthfulness or both.
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Phil{Readers should question why you deny that this science exists when it obviously does and If you want speed limits set scientifically why would you ignore such an important portion of the science on where the safest place to post them is?}
Mr Young(No, the real question is why do you keep claiming that I deny the science when I embraced it well before you ever came onto the scene? I just am unwilling to claim that the science says something that the original researchers did not say.)
There are scientific principles that you specifically deny. The severity of crash issue is one such scientific principle. You go out of your way to disregard it. Other science you embrace very tightly unfortunately that science is only small portions within larger works and the remainder of the works don’t even seem to exist with you. You cherry pick the scienec that best supports your agenda and ignore all the rest of the science, or claim it is insignificant, unimportant or not useful.
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Mr Young(Even more important is the fact that his curve is not a true U-shape but elongated vertically toward the deviations below the mean, more like a slanted reverse-J. What this means is that it is more dangerous to be well below the minimum point than it is to be slightly above it. Of course, most drivers perform this calculus internally and we call that risk homeostasis. The only problem with driving in strict accordance with that internal calculus is that the safest point is usually illegal.)
Risk of crash rises faster above the 85th than it does below the 85th as speeds deviate from the mean. It is NOT more dangerous below the the lowest risk point, it is more dangerous above it. That Solomons work was done on two lane rural roads and vehicles slowing to make maneuvers were over represented, is not justification to then misuse his work to rationalize that on 4 lane freeways where such maneuvers will not be present we should conform speed limits to his risk curve. If more drivers drove in compliance with the law, the lowest point on the risk curve would move toward the speed limit. To suggest that the risk below the minimum point of the risk curve is greater than the risk above that minimum point is intellectually dishonest and selfserving.
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Mr Young(First, why don’t you let me decide what my own goals are? I have outlined them clearly in a prior post. Next, according to NHTSA in 2000, we had approximately 6,356,000 crashes, of which 37,526 were fatality crashes; that is 0.59% of crashes. Your 33% is absurd and that is why no nobody here takes you seriously.)
Dishonest to the end eh Mr Young? In 2000 there were 6,356,000 crashes of those 4,286,000 were property damage only, 2,070,000 were injury crashes and 37,409 fatal crashes. 2,070,000/6,356,000 =32.5676526%. I said 33% were casualty crashes meaning someone was injured or killed. Now everyone can see just how dishonest you are being.
Casualty in this context means a person who is injured in the crash. Note that the Property damage and injury tolls add up to the total number of crashes and that fatality crashes are a subset of the injury crashes.
Casualty:a person or thing injured, lost, or destroyed : a victim
Victim:one that is injured, destroyed, or sacrificed under any of various conditions – a ? of cancer – a ? of the auto crash – a murder
One of Mr. Mckrackin’s several proposals is to correctly round (or round up) the 85th and then enforce it with essentially zero tolerance. He said ” However I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed.” This is totally impractical and would lead to a court system that clogged rapidly shut. Americans will NEVER accept tickets at +1 or +2, regardless of the method of setting the limit. Regards, Jim Walker
PMc writes: {It doesn’t matter who Janice Fisher is or what her position on this issue is.}
You quoted her as though her question was a revelation of enormous magnitude but when I pointed out what a negative representative she was, all of a sudden it doesn’t matter who she is.
{ Does her position on this issue change the fact that it is true that we’re more likely to be killed in a crash the faster we’re going?}
Unsurprisingly, PMc is once again too simplistic because he ignores a lot of significant material. We economists use the phrase ceteris paribus, meaning to hold all other things the same, usually in order to isolate the effect of one phenomenon on another or as a teaching device. The only problem with this assumption is that it never holds true because the real world isn’t like that. So, too, it is with PMc’s claims. We have gone to great effort and cost, using vast resources, to mitigate the known kinetic energy at any given speed. Obviously, the KE does not change but that is less important than that we can now disperse the energy with good effectiveness. The world has changed around Solomon and PMc; Solomon would have embraced the change; PMc would rather cry that we’re out to get him.
The key element of Solomon, the thing that we must take from his landmark work is the methodology of determining the crash incidence curve because it was new and revelatory and can still be used on different roadways and different circumstances. The “revelation” that KE increases as the square of speed was essentially gratuitous, something that we had known for about 300 years.
{That we design ways to decrease the amount of kinetic energy . . .is not justification to then arbitrarily increase the amount of kinetic energy present in the crash exponentially with higher speeds.}
Certainly it is. That is exactly why all that effort has been expended. Why else would we expend all that effort, knowledge, time and resources if we should never use it? Are you really that incognizant of the value of higher speeds translating to higher productivity?
{This challenge is a dishonest attempt to mitigate the effects that kinetic energy has on a crash.}
No, it’s not. It is an attempt to get you to think outside your limited little world.
{I agree with placing speed limits at the point where the crash-incidence curve is at it’s peak low point [whatever that is]. Rounding is just another way for you to justify greater speeds.}
No, rounding is just a mathematical nicety to make it easier to understand.
{ However I would gladly post limits at the point on the crash incidence curve rounded to the next 5mph increment if an enforcement grace was not expected from those who would exceed even that speed.}
As Jim Walker has already astutely pointed out, that would be impractical. In fact, it is too bizarre to contemplate and impossible to implement. A bad policy is one that, among other factors, cannot be effectively implemented; your offering is a classic example of that.
{In the event that you do require an enforcement grace I would lower the speed limit by that amount(If you require a 5mph grace then find the 85th round to the next 5mph incremment and subtract 5mph) so that we are not compounding errors above the 85th that may lead to unintended consequences.}
What in the hell does that mean?
{So Randy and I can expect censorship efforts against us?}
What a bizarre response. (1) It does not follow from the discussion, (2) the NMA does not work that way, (3) I don’t want you censored because I want your silly diatribes exposed, thus making the safety cabal look conspicuously stupid.
PMc writes: [sic] {My Plan is to disallow the stacking of speeds that get rationalized.}
Whatever that means.
{An additional point that I was making is that if Mr Young was aquainted with Solomons work why would he tell me that Solomon’s work did not include work regarding an increases in crash severity with increasing vehicle speeds. }
I said no such thing. I only point out that the inclusion of that verbiage was far from the central point of his work and was essentially gratuitous. That you cannot differentiate important concepts from less important or even trivial is your own shortcoming, not dishonesty on my part.
{John [Carr] an NMA activist paraphrased Braceras’ comments in a light favorable to the agenda of the NMA. He specifically left out important information to portray the story as being proof of the NMA’s agenda.}
Carr omitted nothing and added nothing to Braceras’ or the UDOT press release. KSL (radio and television) and the Deseret News (Salt Lake Valley daily) report the same thing Carr reported.
{You do not consider all the science and even within the works you cite you only accept portions of the works.}
Not quite true. More importantly, academics must be able to ascertain the relevant and important parts of any body of work and ignore the rest. It would be impossible to include all of every work in each subsequent work and knowledge would suffer. In the case of Solomon’s alleged physics work, it was not a significant finding, nor was it even new. It was, in fact, about 300 years old. Do you evn have an idea how trivial a point that is compared to his major finding? It is as though I found a lost Rembrandt and you complain because I didn’t describe the broken frame. How dishonest you are!
{ . . .several other researchers have affirmed his conclusions and some of those have formulated such a “casualty crash curve”. That you seem clueless about it’s existence is evidence of your ignorance, untruthfulness or both.}
I am aware that efforts have been made to formulate a “fatality crash curve.” Note that I am using the more neutral and more exact language of NHTSA rather than PMc’s vague bizarre world terminology. The problem still obtains how do we differentiate between a crash at 50 mph that killed 4 people and one at 51 mph that resulted only in property damage? Do not get me wrong; I have no problem with the concept of creating such a curve for we might learn something valuable from it. But the practicalities of constructing a meaningful, widely-accepted curve probably preclude it as a useful tool in our arsenal.
{You go out of your way to disregard it. Other science you embrace very tightly unfortunately that science is only small portions within larger works and the remainder of the works don’t even seem to exist with you.}
??
{Risk of crash rises faster above the 85th than it does below the 85th as speeds deviate from the mean. It is NOT more dangerous below the the lowest risk point, it is more dangerous above it.}
That is just flat wrong. Look at the Solomon curve. Note how the crash incidence curves turns up as we move to the left of the minimum point. More crashes mean more risk below the speed at the minimum point (the 85th percentile). Note also how the curve turns up to the right of the 85th percentile but not nearly as steeply as below.
What you should be taking from Solomon is his methodology, his crash incidence curve shape and location; and you should be taking his application of the scientific method to traffic safety.
{Casualty in this context means a person who is injured in the crash. Note that the Property damage and injury tolls add up to the total number of crashes and that fatality crashes are a subset of the injury crashes.}
With all due respect, I’ve never seen anybody define “casualty” with respect to vehicle crashes as anything other than fatality, i.e, death. “Casualty” as “injury” is too vague and not in general usage, certainly not by NHTSA. You take these weird journeys down Lewis Carroll’s rabbit hole at your own risk.
Quote from anothe NMA editorial “The report is out. The effects were nil. The fastest 85th percentile speed was 85 mph before and 85 after. Accidents did not change significantly. Speed variance increased slightly without other effect.”
Also note that Mr Young is neither degreed in engineering nor licensed sa a traffic engineer
Also you should note that Mr Young is neither degreed in the engineering field nor licensed as a traffic engineer.
The science that Mr Young, Mr Walker and the NMA have been citing and suggesting we use to correct speed limits tells us that Geater safety benefits are achieved by decreasing the speed variance. That Utah posted a higher limit and the speed variance increased indicates that there is more risk. That the author wrote “Accidents did not change significantly” Implies that crashes did increase but the writer believes the increase to not be statistically significant(note the lack of a link to check the study yourself). Why would the writer NOT tell you that crashes increased, tell you the numbers and let you decide if it was enough to matter? Because the NMA’s who strategy is to fill your head with factually incorrect data that supports their agenda(they are brain washing you, because they know you won’t check the facts). Why else would they get upset when someone suggests that you check the facts?
PMc writes: {That Utah posted a higher limit and the speed variance increased indicates that there is more risk.}
It indicates no such thing but is an example of your dishonesty. Speed variance CAN result in increased risk – manifested in higher crash rates, which, notably, did not obtain here – or it can be mitigated by good lane discipline or light traffic. Having spent several years in Salt Lake City, I can vouch that lane discipline is good, not the best but good enough. If faster traffic does not have to alter path or speed to avoid slower drivers, risk is averted.
{That the author wrote “Accidents did not change significantly” Implies that crashes did increase but the writer believes the increase to not be statistically significant. Why would the writer NOT tell you that crashes increased, tell you the numbers and let you decide if it was enough to matter?}
We do not know that crashes increased; that is your interpretation because it fits your agenda. This is another example of your dishonesty. Crashes could have decreased or remained static but UDOT does not address this event at all. Still, the important factor for analytical purposes is statistical significance because that implies change due to something other than random chance. That nothing happened is important.
{ Because the NMA’s who strategy is to fill your head with factually incorrect data that supports their agenda(they are brain washing you, because they know you won’t check the facts). Why else would they get upset when someone suggests that you check the facts?}
NMA’s strategy is to present the facts for those who have the ability to understand them and with a desire to learn from them. Obviously, you have opted out of this group.
The narrower the speed dispersion, the less the spread between the average speed and the 85th percentile speed, the greater the safety benefits. Since the author has noted greater speed variances the speed dispersion is spread out and therefore having fewer safety benefits. Whether or not the risk actually manifests into crash is the question we need to ask.
The author eluded that “accidents did not change significantly”. If accidents did not chage the author would have noted that because that would support the NMA agenda more vigorously. Similarly if the change that we now know to have happened was a decrease in crashes, the author would have noted that because it better supports the NMA agenda. I do not have the figures for Utah crashes but I would bet that if someone were to find them there would be an increase in the number of crashes experienced after the speed limit increase. It is a much more likely scenario that the number of crashes did increase based upon what the author has said. That the author has placed a value of non significance on the increased amount of crashes does not mean it is actually insignificant, only that calling it insignificant better supports the NMA agenda. If the NMA wants to present the facts why are you so against me encouraging other readers to check the facts that YOU and other NMA members publish in these pages. That I choose to view all the facts and not just those you hand pick to support your personal agenda does not mean I lack the capacity understand them or learn from them. You as every other NMA member I have ever chatted with hold the narcassistic position that if I don’t accept your personal interpretation of ONLY small portions of science then I must be inept. I have pledged my support of correcting limits to levels that are more reasonable to todays actual travel speeds. I however see the irresponsibility that you and the NMA approach this issue with. Waht is your motto again “higher speed limits at any cost”?
Tell me Mr Young, Solomon(1964) included a crash curve that referenced risk of casualty crash with speed and the overal risk of crash referenced to mean speed. Why is it that you refer to the overall crash risk but never address the casualty crash risk. This work has been duplicated and expanded on in several othe studies but you never reference any of those, why? This is a prime example of your choosing science that fits your pre-concieved conclusions. certainly if you feel Solomon(1964) unbiased enough to use his crash risk curve his work would be equally unbiased with the casualty crash curve. However, being an NMA member you discount anything that has to do with risk of casualty crash because ANY study that deals with risk of casualty crash has found that the risk of casualty crash increases with travel speed. Something every NMA member steers clear of because you can’t rationalize your agenda around a curve that shows risk to increase as speed increases and risk above 60mph increases substantially and risk above 70mph increases sharply thereafter.
PMc writes [sic]: {The narrower the speed dispersion, the less the spread between the average speed and the 85th percentile speed, the greater the safety benefits. Since the author has noted greater speed variances the speed dispersion is spread out and therefore having fewer safety benefits. Whether or not the risk actually manifests into crash is the question we need to ask.}
In the Utah case, that question was already answered, as I already noted previously. You can continue to parrot the assumption or, if you want to be truly intellectual we can examine why the phenomenon occurred to see if we can learn something from an increase in dispersion without a corresponding increase in crashes.
{The author eluded that “accidents did not change significantly”. If accidents did not chage the author would have noted that because that would support the NMA agenda more vigorously. Similarly if the change that we now know to have happened was a decrease in crashes, the author would have noted that because it better supports the NMA agenda.}
There you go again, dishonestly assigning sinister motive to something of which you have no knowledge. The “original author” was John Braceras, Deputy Director of the Utah DOT, not somebody with NMA.
{ That the author has placed a value of non significance on the increased amount of crashes does not mean it is actually insignificant, only that calling it insignificant better supports the NMA agenda.}
Non-significance has a very specific meaning in statistics. Arbitrarily assigning malevolence to somebody because it better supports your agenda is but another example of your dishonesty.
{ If the NMA wants to present the facts why are you so against me encouraging other readers to check the facts that YOU and other NMA members publish in these pages. That I choose to view all the facts and not just those you hand pick to support your personal agenda does not mean I lack the capacity understand them or learn from them. You as every other NMA member I have ever chatted with hold the narcassistic position that if I don’t accept your personal interpretation of ONLY small portions of science then I must be inept.}
You are correct. However, your questions and observations support the inescapable conclusion that you do not understand them. When you misstate, misuse or go off on some irrelevant tangent, that means you do not understand them.
{Tell me Mr Young, Solomon(1964) included a crash curve that referenced risk of casualty crash with speed and the overal risk of crash referenced to mean speed. Why is it that you refer to the overall crash risk but never address the casualty crash risk.}
No, in fact David Solomon referenced no such “casualty crash curve.” He did produce a seminal work relating crash incidence as measured by deviation from mean speed, a landmark work because it gave the first academic look at traffic safety and pointed out that the claims of the safety cabal – as speeds increase, the likelihood of crashes and deaths increase (sometimes exponentially) – were false and self-serving. There is no such thing as a Solomon “casualty crash curve,” certainly not one that means injury OR fatality, thus contradicting the meaning of “casualty.” That you do not know this means that you don’t know what you’re talking about.
Could we construct a “casualty crash curve”? Yes, but it would be very vague because the risk of a fatality in a crash depends of many more variables than the speed of the vehicle immediately prior to the crash. I am far less likely to be a fatality at 70 mph in my Bimmer than at even 50 mph in a 55 Oldsmobile. Therefore, the graph would be essentially meaningless.
{However, being an NMA member you discount anything that has to do with risk of casualty crash because ANY study that deals with risk of casualty crash has found that the risk of casualty crash increases with travel speed.}
I discount it because as I pointed out supra, it’s meaningless.
In the Utah case the question was not answered. We can not answer it until we know if more crashes occurred, if less crashes occurred or if the crashes stayed the same. That is purposefully why the author left out the information about the crashes so he could misdirect the readers along the lines of the NMA agenda. If we find out that the phenomenon of an increase in dispersion did not have a corresponding increase in crashes we can examine why that happened, but I doubt we will need to my money is on the NMA member omitting the information to alter the appearance of what happened in Utah.
If John Braceras, Deputy Director of the Utah DOT, was the original author why was the article attributed to John Carr, NMA Activist?
John Carr assigned that Accidents did not change significantly to the number of increased crashes and then witheld the data regarding the crashes in an attempt to support his agenda, so my assigning malevolence was anything but arbitrary.
I believe that I have a good understanding of the principles and how to apply them in these circumstance. However, the issue isn’t whether I understand or accept them when all I am doing is encouraging others to read the facts and not just blindly accept what the liars at the NMA tell them to be true.
It has been a while since I read Solomon(1964) but I clearly recall his conclusion about Day/night Accident Involvement Rate by Variation from Average Speed and his conclusions about day/night Accident Involvement Rates by Travel Speed. The issue still remains that you do not accept the science regarding the casualty crash curve. Solomons work did not prove, as speeds increase, the likelihood of crashes and deaths increase (sometimes exponentially), were false and self-serving. Because, with regards to speeds above the 85th percentile speed that is exactly what his work proves. “The relationship between travel speed and the severity of injuries sustained in a crash was examined by Solomon(1964), who reported an increase in crash severity with increasing vehicle speeds on rural roads. From an analysis of 10,000 crashes, Solomon concluded that crash severity increased rapidly at speeds in excess of 60 mph, and the probability of fatal injuries increased sharply above 70 mph.” A casualty crash curve does exist in at least 3 other works that I can recall at the moment O’Day and Flora (1982), Joksch (1993), Kloeden et al. (1997). That you don’t know that Solomon examined this only proves that you don’t know as much as you pretend to. Readers should question why you deny that this science exists when it obviously does and If you want speed limits set scientifically why would you ignore such an important portion of the science on where the safest place to post them is? It is not meaningless IF SAFETY IS THE GOAL. But then safety has never been your goal or the NMA’s goal. 33.6% of traffic crashes in 1999 were casualty crashes, 33% in 2000 were casualty crashes why then do you use casualty crashes as a measure of safety yet not use the applicable curve to choose the safest speed to post on the sign?
Solomon’s work was primarily on surface highways with 1950s and early 1960s cars. The results today on freeways in modern cars are quite different – as indicated by the 2 to 4 times lower fatality rate on freeways today compared with surface highways, even with the higher speeds involved today. Regards, Jim Walker
Solomon’s work was primarily on surface highways with 1950s and early 1960s cars. The results today on freeways in modern cars are quite different – as indicated by the 2 to 4 times lower fatality rate on freeways today compared with surface highways, even with the higher speeds involved today. Regards, Jim Walker
The point I was making is that you ignore parts of Solomons work simply because they don’t support your agenda. If his work with crash incidence was found using late 1950′s and early 1960′s vehicles and is sufficient for you to cite then why is his work that reported an increase in crash severity with increasing vehicle speeds on rural roads so unacceptable? Other than it doesn’t support your agenda. All of his work has been re-affirmed by other researchers; O’Day and Flora (1982), Joksch (1993), Kloeden et al. (1997)
An additional point that I was making is that if Mr Young was aquainted with Solomons work why would he tell me that Solomon’s work did not include work regarding an increases in crash severity with increasing vehicle speeds. That he did not said within these pages that Solomon’s work did not include such subject matter or conclusions points to his ignorance or his untruthfulness.
Solomon’s low point on the risk curve was in the mid-60s mph, still true today in most places for surface highways. Remember the 1941 NSC report that put the 85th on rural MO highways in 1940/41 at 62.5 mph and the last NMSL report in MI in 9/95 which showed 85ths of 63-69. If you had to use one number nationwide for good rural surface highways in non mountain areas — it would be 65, the same limit that was used by MI and IN and many other states before the counter-productive NMSL entered the picture. As Mr. Mckrackin knows, I do NOT support blanket one-size-fits-all statutory limits, I support legitimate traffic investigations and speed surveys for every road. Texas has done that with rural highways and you will find surface highways posted at 45, 50, 55, 60, 65, and 70 — as they found appropriate for each individual area. Using 85th limits is almost always correct – individually measured and posted. Regards, Jim Walker
I am not under the same self-imposed constraints as Jim Walker. I do not even pretend to respect Phil McKrackin’s opinion, his intellectual acumen, his analysis, or his honesty. I submit that PMc is a fraud, a shill sent or instigated by an agency within the cabal that benefits personally, professionally, financially or in terms of control by imposition of speed limits that do not meet science-based criteria or other anti-motorist laws. One need only read his confused, obtuse, poorly constructed “arguments” to determine that his scholarship is deficient, his logic incorrect, and that he often parses phrases or individual words past the point of relevance into the realm of the absurd. He writes known-false assertions with the intent to deceive, the classic definition of a lie.
He has turned what used to be a delightful and educational experience into torment, an anti-intellectual trip through PMc’s personal fantasyland. While both Jim Walker and I have shown PMc to be foolish, ignorant and mean-spirited, he is too stupid to know when to give it up, instead arguing esoteric and now meaningless points.
I will respond to some of his “points” later. Right now I have to go scrub myself with Betadine.
A shill sent here by the safety cabal to encourage the readers to check the facts? If The safety cabal was the pack of liars that Mr Young, Mr Walker or the NMA accuses them of being, my encouragement to check the facts should be construed as support of the NMA, Mr Young and Mr Walker. Mr Young’s immediate accusation of my being a shill working for the “Safety Cabal” comes on the heal of my encouraging readers to check the facts, I would submit that Mr Young doesn’t want you to check the facts(he wants you to accept his interpretations of the science and what should happen with the speed limits). If Mr Young’s position is so honest and his analysis so correct he too should encourage that you check the facts, but that isn’t happening. Instead he will call some who is encouraging the checking of facts as dishonest. If he is discouraging that you check the facts it should imply to you that the facts will not support his lies. Mr Young suggests that he wants science based criteria used in setting the speed limits yet he ignores the science of Sir Issaac Newton(1687). He also rejects the science of Solomon(1964), Munden (1967), O’Day and Flora (1982), Fildes, Rumbold, and Leening (1991), Fildes and Lee (1993), Joksch (1993), Bowie and Waltz (1994), all that deal with the issue of crash severity and the risks of casualty crash(crashes that result in injury or death).
Apparently by encouraging readers to check the facts I have turned what used to be a delightful and educational experience into torment. Delightfully educating for whom? Certainly not the people who he is lying to, brainwashing educates no one. Again I submit that if Mr Young is providing us with facts why would he be so against me encouraging others to read the facts?
I also would ask that if I am supportive of increasing speed limits to rational speeds for all roadway users but disagree with the irresponsible manner in which Mr Young and the NMA promote those increases what would the false assertions be that I am supposedly writing? That it would be correct to increase speed limits using a scientific based method. I support using science to correct limits to more reasonable levels. I however do not support using only select pieces of science to justify the increases while separately ignoring other science that may give us additional information on where the best place to post the limits actually is.
I submitted a detailed analysis of where the safest area to set the speed limits was to Mr Walker along with a suggested plan that would increase speed limits to a point where enforced with a small grace would always result in enforcement being against drivers who were exceeding the 85th percentile speed and only those who were exceeding it by enough speed to be in the high risk portion of the simple crash risk curve. However because that plan didn’t involve allowing speeds in excess of the 95th percentile, he outright rejects it.
I stand by my post. I believe that PMc is a shill of the safety cabal and his latest offering does nothing to dispel that.
The following quotes in brackets{} of Phil Mckrackin are copied verbatim; any errors are in the original: {If The safety cabal was the pack of liars that Mr Young, Mr Walker or the NMA accuses them of being, my encouragement to check the facts should be construed as support of the NMA, Mr Young and Mr Walker. Mr Young’s immediate accusation of my being a shill working for the “Safety Cabal” comes on the heal of my encouraging readers to check the facts, I would submit that Mr Young doesn’t want you to check the facts(he wants you to accept his interpretations of the science and what should happen with the speed limits). If Mr Young’s position is so honest and his analysis so correct he too should encourage that you check the facts, but that isn’t happening.}
While most of that is not even comprehensible English, let the word be spoken clearly and without distortion: I support and encourage any reader here and any person who is interested in valid public policy to do the research, not just on the Internet, which offers dangers as well as opportunities, but to go to law and engineering libraries. Researching a topic as complex and as diverse as traffic safety will lead one into law, statistics, psychology, engineering, history, public policy, and physics. However, because there is an element of our society that benefits from manipulation of traffic laws, we are also offered much false information.
Let’s also talk for a minute about the safety cabal. These are the industries, institutions, agencies and people who have a vested interest in keeping speed limits below where science says we should place them. Usually, the interest is financial although increased control is rising as a factor. Would PMc have us believe that the insurance industry that stands to profit in the tens of billions from too-low limits would actually tell us the truth, which would expose their fraud?
I also encourage all people to take a college-level course in critical thinking, one in logic and one is statistics. This is not my first support or encouragement of examining the full body of facts because I have called for it many times right in these fora as well as others.
{ Instead he will call some who is encouraging the checking of facts as dishonest.}
No, I label you as dishonest because you misinterpret what people have written – either through ignorance or malice — ignore what are obvious conclusions and dwell on the trivial at the expense of the meaningful. In subsequent posts, I’ll highlight some of these.
{Mr Young suggests that he wants science based criteria used in setting the speed limits yet he ignores the science of Sir Issaac Newton(1687).}
Do you not realize that alluding to Newton is dishonest because he is irrelevant to the discussion? You are merely trying to pad an otherwise vacuous argument.
{ He also rejects the science of Solomon(1964), Munden (1967), O’Day and Flora (1982), Fildes, Rumbold, and Leening (1991), Fildes and Lee (1993), Joksch (1993), Bowie and Waltz (1994), all that deal with the issue of crash severity and the risks of casualty crash(crashes that result in injury or death).}
Far from rejecting these pioneers, I embrace them but I also do not assign meaning to them that they never intended in a dishonest attempt to pervert their meaning. Once again, PMc conjures up some virulent meaning to assign to me in a feeble attempt to minimize my argument.
{Apparently by encouraging readers to check the facts I have turned what used to be a delightful and educational experience into torment.}
No, it is about your obtuse views, your casual adherence to fact, and your inability to distinguish between opinion and fact, not to mention your constant demand for proof and then your inability to understand the proof when presented.
{I also would ask that if I am supportive of increasing speed limits to rational speeds for all roadway users but disagree with the irresponsible manner in which Mr Young and the NMA promote those increases what would the false assertions be that I am supposedly writing?}
You keep confusing the application of established science by saying what we support is irresponsible even though the consensus of scientists and engineers in the field and the empirical data support what we say. You try to dishonestly conflate the pace with the 85th percentile as though the difference were important rather than trivial.
{ That it would be correct to increase speed limits using a scientific based method. I support using science to correct limits to more reasonable levels. I however do not support using only select pieces of science to justify the increases while separately ignoring other science that may give us additional information on where the best place to post the limits actually is.}
Wrong. The fact is that the science supports setting limits at the 85th percentile, rounded up to the next higher 5 mph increment. You go to great lengths and much malleability of fact to excuse keeping limits low.
{I submitted a detailed analysis of where the safest area to set the speed limits was to Mr Walker along with a suggested plan that would increase speed limits to a point where enforced with a small grace would always result in enforcement being against drivers who were exceeding the 85th percentile speed and only those who were exceeding it by enough speed to be in the high risk portion of the simple crash risk curve. However because that plan didn’t involve allowing speeds in excess of the 95th percentile, he outright rejects it.}
As well he should. Do you not understand the basic shape of the crash-incidence curve is a U and rises much faster to the left of the minimum than to the right of the minimum? Further, do you not realize that enforcement should focus on dangerous behavior rather than an arbitrary speed, even if it exceeds the 85th percentile?
Phil{Mr Young suggests that he wants science based criteria used in setting the speed limits yet he ignores the science of Sir Issaac Newton(1687).}
Mr Young(Do you not realize that alluding to Newton is dishonest because he is irrelevant to the discussion? You are merely trying to pad an otherwise vacuous argument.)
Do you realize that the science of Newton is very relevant to the discussion? Have you ever heard of Newton’s laws of motion, Kinetic energy. When you discuss crash severity Newton becaome extremely relevant. The only way that his science would not be relevant is if the laws of physics ceased to exist as they obviously have in your world.
Phil {He also rejects the science of Solomon(1964), Munden (1967), O’Day and Flora (1982), Fildes, Rumbold, and Leening (1991), Fildes and Lee (1993), Joksch (1993), Bowie and Waltz (1994), all that deal with the issue of crash severity and the risks of casualty crash(crashes that result in injury or death).}
Mr Young(Far from rejecting these pioneers, I embrace them but I also do not assign meaning to them that they never intended in a dishonest attempt to pervert their meaning. Once again, PMc conjures up some virulent meaning to assign to me in a feeble attempt to minimize my argument.)
If you embrace them then how is it you didn’t know that the relationship between travel speed and the severity of injuries sustained in a crash was examined by Solomon (1964), who reported an increase in crash severity with increasing vehicle speeds on rural roads. From an analysis of 10,000 crashes, Solomon concluded that crash severity increased rapidly at speeds in excess of 60 mph, and the probability of fatal injuries increased sharply above 70 mph. If you embrace them then why do youignore the severity of crash which is demonstrated by these works to be very relevant to the issue of where the safest point to post the speed limit is?
Phil{I submitted a detailed analysis of where the safest area to set the speed limits was to Mr Walker along with a suggested plan that would increase speed limits to a point where enforced with a small grace would always result in enforcement being against drivers who were exceeding the 85th percentile speed and only those who were exceeding it by enough speed to be in the high risk portion of the simple crash risk curve. However because that plan didn’t involve allowing speeds in excess of the 95th percentile, he outright rejects it.}
Mr Young(As well he should. Do you not understand the basic shape of the crash-incidence curve is a U and rises much faster to the left of the minimum than to the right of the minimum? Further, do you not realize that enforcement should focus on dangerous behavior rather than an arbitrary speed, even if it exceeds the 85th percentile?)
How could you possibly conclude that I do not understand the basic shape of the risk incidence curve. That is just a blatent attempt to discredit my argument even though I have many times told you I support increasing speed limits to rational levels. Parker said that the greatest safety benefit was to be had by posting speed limits within 5mph of the 85th and other works that I have read specifically show that the lowest point on the crash risk curve occurs between the 85th percentile and the 50th percentile. Apparently you have examined this risk curve about as closely as you read Solomon(1964). If you examine the curve closely you’ll see that the if we examine only the risk of crash and we find the point along it where it crosses the verticle line of the average or mean speed then you draw a horizontal line to the right and find the point where this risk level again crosses the risk curve you’ll note that the mean or average speed is about 5mph below the 85th and the point of equal crash risk is only 2.5-3mph above the 85th. It is very obvious that the right side increases in risk at a greater rate than the left side does. Speeds above the 85th are more dangerous than speeds below the 85th. Even the two points I described that seem to have an equal crash risk the one above the 85th is much more dangerous than the one below the 85th from a severity standpoint. “Clearly, a research or engineering approach to speed management that ignores the injury consequences of vehicle speed could lead to unintended results.”
Mr. Mckrackin’s plan was to ALWAYS round down to the 5/0 interval below the actual 85th – a procedure I have never seen recommended in ANY research. The overwhelming amount of research says either to 1) round up or down to the nearest 5/0 interval, OR 2) always round up to the next higher 5/0 interval. I found his method to be better than today’s chaos of limits set 10, 15 or 20 mph below the 85th, but not nearly as good as the overwhelming body of research dating back 70 years. Parker said to post “within 5 mph” of the 85th in order to set a limit of how far below the real 85th that engineers could go. At the time of his major research in the early 1990s, it was common to have state rules allow posting 7 or more below the 85th, and he wanted to put a limit on that practice. Regards, Jim Walker
My Plan is to disallow the stacking of speeds that get rationalized. If the 85th is the safest place to set the limits I have no problem with doing that. I also have no problem with rounding up, down or both. However if this is a corrected limit I see no rationalization for drivers who choose to exceed it something Mr Walker intends to stretch all the way upto the 99th percentile speed which is unacceptable if the safest point to set limits is elsewhere.
Mr Walker is well aware that I would accept his method of 1)rounding up or down to the next 5mph increment or 2)rounding up to the next 5mph increment if that was coupled with driver accountability for any of the drivers who would choose to exceed this “corrected limit” The Plan that Mr Walker cited that I proposed is one of many and was proposed in response to Mr Walker’s insistence that this corrected limit be coupled with an additional enforcement grace. Mr Walker would find the 85th round it up 4mph and then add another 5mph before enforcement takes place. the resulting defacto speed limit is now upward of the 95th percentile speed which is obviously NOT the safest place to have it.
Mr. Mckrackin stated my position as: “Mr Walker would find the 85th round it up 4mph and then add another 5mph before enforcement takes place.” This is flatly false, a common exaggeration that Mr. Mckrackin uses to try to make his points. I support rounding the 85th to the NEAREST 5 mph interval, NOT always to round up. Mr. Mckrackin tries to make his points by lying about what my position is, to try to make it seem extreme. He knows better from our more than a year long private discussion, but he tries to make you think my position is different than it is. I support rounding the 85th to the nearest 5/0 interval, so the posted speed limit will never be more than 2 mph different from the 85th. I then would say enforcing at the next 5 (up to 4 mph grace) is correct — because Americans will NEVER accept tickets at +1 to +4 without an enormous percentage taking the issue to court – and quickly clogging the courts shut. At the limiting case where the 85th ends in 3 or 8, rounded up to the next 5 or 0, this means an enforcement tolerance of 7 mph over the actual 85th. In 80% of the cases, the actual tolerance will be 6, 5, 4, or 3 mph. Mr. Mckrackin thinks my method, which matches most of the 70 years of research is too extreme. I think otherwise. I know it would direct the speed-alone enforcement versus about the top 5% (2% – 8% in most cases), the area which I know is proper – AND practical to use to enforce versus the high flyers who are way above the 85th and the pace and whose speed alone MAY cause safety issues. Regards, Jim Walker
20% of the time enforcement will start at 7mph over the 85th, 20% of the time enforcement will statr at 6mph over the 85th, 20% of the time enforcement will start at 5mph over the 85th, 20% of the time enforcement will start at 4mph over the 85th, 20% of the time enforcement will start at 3mph over the 85th. 100% of the time this type of enforcement will allow speeds over the 90th percentile speed with 60% of those times allowing speeds at or above the 95th percentile. If the safest place to travel is near the 85th percentile speed, why then is it so important to Mr Walker, Mr Young and the NMA to find ways to allow speeds well in excess of the 85th percentile speed?
Because you cannot enforce with a tiny or zero tolerance on a high volume road, the numbers do not allow it. Believing you can effectively enforce versus perhaps 10% of the total flow is simply impossible. Should you bring enough officers to do that at some locations, expect total chaos and perhaps many accidents resulting from the chaos. Second, the risk curve on a freeway is different than Solomon's curve shape, it is flatter and rises much more slowly after the 85th for several mph.
ALL of the traffic that Mr Walker suggests to go unpunished, increases the risk of crash to the entire speed distribution and increases the risk of casualty crash(meaning a crash that involves an injury or death) at an exponential rate to the entire speed distribution. Traveling at speeds above the 85th percentile speed is much more dangerous than traveling at speeds at or below the 85th percentile. So lets use science to set the limits so that the super majority(85%) of traffic is at or below the the limit. Then we can enforce against the law breakers who are adding risk to the entire speed distribution by enforcing to anyone who exceeds the posted limit(why is it so important to allow a grace?)
Same reply as above, enforcing tightly versus perhaps 10% of the total flow is not possible. Also, the risk curve for freeways has only slightly higher dangers for the few mph above the 85th – the curve shape is flatter at the bottom.
You forget that I have viewed the risk curves and Know that the risks above the 85th are always higher than those below when viewed as deviation from the 85th percentile speed. So your answer is to allow the unlawful behavior as if it were lawful? WHY NOT JUST POST THE LIMIT HIGHER? Part of the problem we are experiencing today with speed limits is that enforcement doesn't happen at the number on the sign. Whatever, corrections you make to the speed limits will be a waste of time and resources unless you reform the way enforcement action is taken.
I believe, and most authorities agree, that posting the 85th is correct. I do not believe that Americans will EVER accept tickets at +2 or +3, so I do not ever consider that to be a practical or achievable practice. I completely agree we need to reform the enforcement regimen — it is nonsense to have today's very low limits and grace allowances of +10 or +15. It makes a mockery out of the whole process. A correct limit and a small grace are the answer that drivers would accept. A higher limit and zero tolerance would not be accepted, regardless of the posted limit.
I have agreed that speed limits need to be increased to somewhere near the top of the pace/85th percentile. So I don't get why you contantly attribute me as wanting something other than that. I believe that the major problem with the enforcement system is it's allowing enforcement graces. How can you expect motorists to respect and comply with a speed limit that you don't enforce? Ironically this is the same problem that your methodology suffers. Correcting limits will only bring us long term safety benefits if we reform the enforcement system. Reforming the enforcement system will only work if we correct the limits. Neither will work without the other. You can say all the experts agree that this will work or all the experts and I agree that will work but in reality unless the limits and enforcement are corrected we will end up at square one in a few years with all the little babies at the NMA crying that speed limits are underposted and purposefully done so that revenue can be gained. Grow up, anyone who has looked at this issue in any depth knows that the blaming revenue is nothing more than a propaganda trick to cause motorists to distrust the government and/or speed limits.
Lets be clear here. I want speed limits posted AT the 85th, rounded to the nearest 5 interval, so that most posted limits are no more than 2 mph above or below the actual 85th. "Somewhere near the top of the pace/85th percentile" leaves too much room for arbitrary judgement for the normal cases. (YES, there should be some exceptions, but as the unusual exceptions only where the hazards are not readily visible to the average driver.) I also agree the enforcement system needs to be reformed at the same time as the posted limits. However, I see a huge difference between a 1 to 4 mph grace over an 85th limit, versus a 10 to 15 grace over a 30t, 20th or 10th limit. Yes, both are graces, but the small grace over a correct limit is logical and will be accepted by virtually every driver as appropriate. If reforming the enforcement regimen means issuing tickets at +2 or +3 over a correct limit, I believe that system would immediately fail as unacceptable to most drivers. Mr. Mckrackin also obviously fears a fairly fast creep in freeway speeds if a grace of up to +4 is allowed, and I find the data says that is not the case. As to Mr. Mckrackin's last sentence above, I believe that anyone who has looked at this issue realizes that – whatever the motivations of any given venue – the revenue result of our 30+ years of incorrect limits is anything but a propaganda trick. Merely suggesting that is nonsense to me.
Nota bene! All of my quotes of PMc are verbatim and contained within brackets {}to set them apart from quotes of third parties and from my own. __ __PMc writes: { I believe that the major problem with the enforcement system is it's allowing enforcement graces. How can you expect motorists to respect and comply with a speed limit that you don't enforce?}__ __The major problem with the traffic enforcement system is that it has morphed into a revenue collection system – at which it is very good – but has essentially zero effect on measurable traffic safety improvements. We have instances where enforcement efforts have intensified and where they have attenuated, all with no discernible effect of key measures of traffic safety, which, empirically, appear to operate independently of enforcement effort or focus. __ __Why is this so? In my judgment, it is because enforcement concentrates on the wrong behavior, eschewing the dangerous for the easy and the profitable. Texas DPS was forced to disclose certain performance data by a federal court. In one year (2000?) they issued just over 1 million citations
If having a grace currently is making a mockery of the whole process why would you insist upon an enforcement grace. A correct limit and enforcement of the limit is the answer but nobody seems to have tyhe balls to say it. It will not be popular because we as a society have grown accustom to being afforded an enforcement grace above the speed limit. WHY is an enforcement grace needed? You say post the limit at the 85th then enforce at the 95th. That can't possibly work long term and only serves to spread the speed distribution out creating more variances and morechances for conflict. The number on the sign needs to be the number that is enforced for the sytem to work properly anything else encourages disrespect for the law.
A SMALL grace of 1 to 4 mph over a correctly posted limit is entirely different than a grace of 10 to 15 or more to accommodate the reality of grossly under posted limits. I believe most students of this issue agree with me on this concept, and not with Mr. Mckrackin. Posting the 85th and enforcing at +1 to +4 or more will fail immediately because drivers in huge numbers will challenge tickets at +2 — AND they will win. The court system will grind to a halt, forcing a change to an unworkable plan. Mr. Mckrackin is not correct to say that posting the 85th and enforcing at the 95th leads to a greater spread in the speed distribution or more variance, that is simply not true.
If you believe the 85th percentile speed will yield the greatest safety benefits to the speed distribution why negate those safety benefits by adding an enforcement grace or allowing non confomance with that corrected speed limit?
See above responses. Americans will NEVER accept tickets at +2 or +3, the system is doomed to immediate failure and I see no reason to even contemplate doing that.
Mr Walker suggests that we set the limits scientifically but then wants to arbitrarily enforce them. If it is so important to set the limits to the safest point why is it not important at all to enforce them at the safest point? If we are going to use science to optimize safety while setting the limits then lets use the science all the way to enforcing the limits by setting and enforcing the limits using science. If we are going to enforce the limits arbitrarily at points above the safest point then we have wasted all the resources used to set the limits at that point.
Because it is NOT possible. Example, 1000 cars per hour, try enforcing versus about 10% of the flow or 100 cars. One officer can cite 4 or maybe 5 of them in one hour. The numbers do not work and Mr. Mckrackin refuses to accept that fact.
So then 4 maybe 5 drivers get cited. Just because there isn't enough enforcement resources does not mean we should allow the behavior. 4 drivers traveling in that 10% will recieve a citation. what about roadways that aren't actively being patroled? Isn't the enforcement resources zero? does that mean we should allow any speed that the motorists can imagine? It is simply ludicris to suggest that we allow unlawful behavior simply because we can't catch all the violators.
If you really want to change the speed distribution by citing those who cause dangers, then you have to focus on the drivers that cause real dangers — the high flyers and the crazies that are far out of the normal speed pattern. This is easy to do with 85th limits, a small grace, and then target those at the limit +5 or higher. They are a small group, their driving can cause conflicts, and we have enough resources to target a significant percentage of them. Randomly giving a ticket to any given driver every few years will achieve nothing.
Any driver who exceeds a new corrected speed limit and therefore exceeds the 85th percentile speed is causing real danger to the entire speed distribution. If we allow their unlawful and unsafe behavior to continue without enforcement other driver's percieve that the behavior is acceptable and fewer will remain compliant to the number on the sign. The speed distribution moves up, the 85th percentile moves up and the NMA is crying like babies again that speed limits are under posted for revenue generating purposes. That isn't what I view as correcting the speed limits or fixing the system. In order to correct the speed limits and fix the system enforcement needs to be against anyone who breaks the law. Until you come up with a solution that targets all those who are in violation of the numbers on the signs you'll be doomed to fail. Politicians know this, and resist increasing limits as much as possible to combat runaway speed limits. Something you apparently refuse to accept and as long as you and the NMA refuse to acept this fact your cause will be doomed to fail.
Corrected limits on surface roads tend to remain stable and speeds do not move up. See Washtenaw. Rural freeway speeds move up by about 5 mph every 10 to 20 years. An average 85th today in MI is 80 mph, about 10 mph faster on average than in the early 1960s. Our fastest freeways measure about 83 mph for the 85th and some sections of Texas freeways posted at 80 measured less than 85 mph for the 85th. The belief that the speed distribution will move seriously or quickly upward is not evidenced in the data. Targeting ALL those in violation of even a perfectly corrected limit is utterly impossible, the numbers don't work. Until Mr. Mckrackin accepts that fact, his proposed solution is doomed to failure before implementation. Fortunately, most venues would not even think about trying to issue tickets for +2 or +3, they would know in advance that such a plan would never be accepted by the public. As students of this issue know, we ARE slowly winning the fight for corrected limits. Even throwback Virginia passed a law to raise many freeway limits to 70 mph to match real speeds and the issue was pushed forward by the Governor of Virginia. We ARE winning, one venue at a time.
You also forget that the small group that you suggest we have enough resources to target are the drivers like you that use electronic warning devices to escape detection meaning no one would be targeted, Outlaw the electronic warning devices and I have am more accepting of such a plan. I still believe it substandard because it encourages drivers to exceed the number on the sign however I'd accept a higher number than the 85th percentile speed on the sign with zero tolerance enforcement and the use of electronic warning devices outlawed.
I could teach any decent officer how to target the high flyers effectively, including those with the best detectors. I would be happy to help do that – AFTER the posted limits are fixed. Note also, I do not advocate posted limits higher than the correctly rounded 85th. No limit would be posted more than 2 mph above the 85th under my plan – the plan that matches most of the research.
Mr Walkers assumes that on this roadway with a volume of 1000 cars per hour that the enforcement agency would/could only assign 1 officer the task of enforcement. This is a rationalization that Mr Walker has thought up to justify his allowing speeds in excess of the 95th percentile. He has told us that the safest place to travel is at the 85th percentile, that is his entire rationalization on why we should post at the 85th percentile, it is much safer there. Now he will suggest to you that allowing speeds upto and in excess of the 95th percentile is "JUST AS SAFE" as the 85th percentile. Given the "U" shape of the risk curve that would also imply that there is a speed below the 85th percentile which is "JUST AS SAFE". If that is so the we should use that "JUST AS SAFE" characteristic below the 85th to offset the enforcement grace that Mr Walker insists needs to be in place above the speed limit.
Mr. Mckrackin HAS reviewed the freeway risk curve developed by Cirillo and others and simply refuses to accept that speeds a bit above the 85th on freeways are only VERY slightly riskier than staying right at the 85th. He is wrong, and he ignores the research that he and I discussed in private in great detail for over a year. It is simply ludicrous to think that issuing one ticket to an individual driver every 4 or 5 years will change overall driver behavior for the whole speed distribution– it will NOT. It is idiotic to think that some very random and very infrequent receipt of a speeding ticket for a 3 over or 4 over violation will be seen as anything other than predatory enforcement by greedy politicians for entirely revenue based reasons.
Mr Walker does not see the forest through the trees. He is so vigorously trying to eliminate predatory enforcement practices that he is willing to forego safety to achieve that goal. It is moronic to suggest that non enforcement will work better than strict enforcement.
IF we had the resources to cite any significant percentage of the total traffic flow, Mr, Mckrackin might be right. However, we do not have those resources, so we need to use them versus the most dangerous drivers — including those whose speed alone may cause hazards. I do NOT advocate non-enforcement, I favor targeted enforcement that can work. Mr. Mckrackin's view of strict enforcement is not achievable, the numbers do not work.
Currently you tell us that speed limits are set under the 50th percentile speed typically at 30th percentile and often at the 10th percentile. This means that 90%, 70% or 50% of the traffic stream is currently being targeted. The NMA also tells us that such a high percentage of the traffic stream is being targeted for revenue pruposes………Cont
No, with common grace allowances, officers try to target about 10% to 25% of the total flow and the tickets are given pretty much at random to an insignificantly small percentage of that flow. We have 35+ years of data to show this is completely useless for any safety purpose — though it certainly produces revenue, much of it taken from some of the safest drivers on the road.
So then 50%, 70% and 90% of the traffic stream is NOT defined as unlawful because a large portion of them fall within the enforcement grace? Even under your proposed methodology tickets will be totally random unless enforcement is increased. Even after you let 2/3 of those exhibiting unlawful behavior pass unenforced against. That is amazing that only 10% to 25% of the total traffic flow is targeted and 22% to 25% of the total flow recieves citations. Your numbers don't make sense. If only 10% of the toatal traffic flow is targeted how does 25% end up with citations. even if we use the other end of your range and 25% are targeted if 25% recieve citations every motorist in the target group was cited.
There is an obvious difference to most people between what is technically unlawful – for example being in the 70% of drivers above a 30th posted limit —- and what might be randomly enforced if you happen to be one of the unlikely ones that day the officer targets almost at random when they are above the arbitrary grace the officer is using that day. Using my method the enforcement will be anything but random – it will be rifle shot targeted versus the top (on average) 5% of the flow. As to the total ticket numbers, some drivers receive more than one in a year. Most get only as much as one ticket every few years, a level that becomes just a revenue annoyance, not a behavior changing punishment.
The 35+ years of data show us that attaching an enforcement grace above the speed limit only leads to non compliance. Ironic that you should be advocating non compliance now and also advocating a methodology that would promote non compliance in the future. Any driver who is exceeding the posted limit is adding risk to other drivers and themselves and cannot be classified as "some of the safest drivers on the road" If those drivers were compliant with the posted limit it would be safer to drive at the posted limit than above it. Just because alot of people are in a hurry and have moved the safest point on the curve up in speed does not make those drivers safe drivers. Safe drivers would comply with the organizational rules of the road including the speed limits whether or not they agree with them.
What has been wrong for 35+ years has been the WRONG limits, thus leading to stupidly large grace allowances to make any ticketing practical. I believe that most people can see how a correct limit plus a small grace will fix both problems at the same time. "Some of the safest drivers on the road" on freeways refers to the sweet spot in the Cirillo research that shows drivers at about 11-16 over the median or average speeds have the lowest accident rate. I accept that research. Mr. Mckrackin's last statement is theoretically true, but we all know it is NOT going to happen with under posted limits and is therefore to me a total waste of time to even discuss that unrealistic outcome that is not going to happen.
Somewhere in the area of 22-25% of the current traffic stream recieves citations for exceeding the posted limits. If we repost to the 85th percentile speed and enforce against anyone above the 90th percentile we have reduced the target pool down by 80%, 85%, 89% respectively. If we cited every violator we will effectively cite 59%-60% fewer drivers than we currently cite. If we don't have the resources are those 59%-60% currently being cited by ghosts?
An insignificantly small percentage of that up-to-25% of the total traffic flow receives citations, and it accomplishes absolutely nothing for safety. It damages safety by having incorrect limits. Reposting to the 85th, correctly rounded up or down, and enforced with a +4 grace so tickets start at +5 will target about 2% to 8% of the top speed range. Given the platoon effect, it probably actually targets the top 1% to 5% of the total numbers, a proportion where enforcement can have some effect over time. People that drive in that range will run a very real chance of getting a ticket and likely more than one ticket over a 2 or 3 year time frame. In most states, this will cause severe insurance surcharges and will have a real component of behavior modification. Citing EVERY violators under any regimen is utterly impossible.
Between 22% and 25% of the total traffic flow recieves citations on a yearly basis. Not a small percentage of that number. It damages safety by not comforming to the speed limit but you and the NMA both encourage non-compliance. Using your 1000 vehicle per hour high volume roadway 150 cars will be non compliant and exhibiting unlawful behavior. between 20 and 80 will be above the enforcement grace and only about 10 to 50 will be enforced against. I am sorry but punishing only 10 drivers when 150 are acting unlawful is far to few to deter the behavior and likely you will NEVER see improved compliance, but in fact just the opposite once the reemainder of the traffic steam realizes it can travel well above the posted limit without suffering enforcement actions
If Mr. Mckrackin's numbers are about right, then consider that some drivers get more than one ticket in a year. Adjust for that and it means any one driver might get one small ticket every four or five years and that becomes just an annoying road tax — NOT a behavior modifying punishment. We need to focus speed-alone enforcement versus those well above the pace and using 85th limits with a +4 grace will do that. It is a relatively small group that is consistently well above the pace and they will risk multiple tickets over the time frame that insurance companies check in most states. Their penalties will mount fast enough for it to be a behavior modifying punishment. Randomly ticketing a driver in that 1-4 grace every four or five years will accomplish absolutely nothing for safety. It will be just an annoying road tax, and one seen to be so punitive that a huge percentage will challenge and the court system will grind to a halt.
Couple that with the fact that MOST of the drivers driving in that range are using electronic warning devices to escape detection and even fewer drivers get punihed for breaking the law. Your methodology does nothing to modify the unlawful behavior and can only succed in making the driving enviroment less safe for many of the roadway users. But as long as you get to drive fast you are happy.
I want to guess that this is Mr. Mckrackin's real fear, his fear that it is too difficult to catch the high flyers and crazies. I could easily teach any decent officer how to target the top 5%, including those with the best detectors. I am happy so long as I can drive in or just above the pace which I have done for many, many years.
I accept it as they published it. I do not embelish upon it or misrepresent what it shows as you and the NMA do. I have read much of the same materials that Mr Walker, some provided by Mr Walker. He claims I refuse to accept them or have simply drawn the wrong conclusions from them. Mr Walker presents his argument as if he were a licensed traffic engineer, he is not. In fact he isn't even degreed in that field, but suggests that I have drawn the wrong conclusions for which he is not qualified to critique. He suggests that issuing 1 ticket to an individual every 4 or 5 years will never modify the behavior causing the speeding. How well will allowing the speeding and NEVER citing unlawful drivers do to deter the behavior?
Americans will never accept tickets at +2 or +3. And, it is most definitely not a waste of resources to set the limits correctly, that statement is false.