The Effect Of Speed Limits On Actual Travel Speeds
August 21st, 2008 Posted in Speed Limits
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
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We've switched our commenting system over to Intense Debate. For more information, read this article.
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….
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….
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.
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).
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]
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…..
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.
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.
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.
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….
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.
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.
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..
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.
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.
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.
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)
—————————————-
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