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Speed Limits: Slower Does Not Mean Safer

Posted on October 6th, 2009 in | 87 Comments

Speed Limits: Slower Does Not Mean Safer
As we’ve noted many times in the past, speed limits are the most safe when they are set using the 85th percentile speed.

Numerous studies have shown that the 85th percentile is the safest possible level at which to set a speed limit, but the excerpt below (from a booklet released by the Michigan State Police) is particularly effective at explaining this point:

The primary basis for establishing a proper, realistic speed limit is the nationally recognized method of using the 85th percentile speed. This is the speed at or below which 85% of the traffic moves. For example, if 85 of each 100 motor vehicles were recorded at 45 mph or under, then 45 mph is the 85th percentile speed.

Historically, before and after traffic engineering studies have shown that changing the posted speed limit does not significantly affect the 85th percentile speed. The driving environment, which includes other traffic on the road and roadway conditions, is the primary factor which influences the prevailing speed.

The driving environment is reflected by the 85th percentile speed. The majority of drivers, consciously or unconsciously, consider the factors in the driving environment and travel at a speed that is safe and comfortable regardless of the posted speed limit.

The speed data are collected by recording the speeds of free flowing motor vehicles using a radar or other speed measuring device. A representative sample of vehicular speeds is recorded and these speeds would include local residents who drive through the zone.

Use of the 85th percentile speed acknowledges that 15% of the drivers are traveling above a speed that is reasonable and proper. This is the 15% of motorists at which enforcement action is directed. Studies have shown that this is the group of motorists that cause many of the crashes and have the worst driving records.

There are other parameters used to evaluate speed data, such as the average, median and pace speeds. However, the 85th percentile speed is the most critical criterion in establishing realistic speed limits.

The graph included below (from the Texas State Department of Highways and Public Transportation) shows the relationship between the 85th percentile and a motorist’s chance of being in an accident:

Speed Limits: Slower Does Not Mean Safer

Unfortunately, most speed limits are set well below the 85th percentile speed. When speed limits are set too low, drivers are forced to travel at a speed that increases their risk of being involved in an accident. The alternative is to travel at the safest (85th percentile) speed and risk a speeding ticket. This is something that many drivers do everyday.

The NMA has been fighting back against unrealistic speed limits for years (starting with the 55 MPH National Speed Limit), but we need your help to spread the word. Send this article to your friends, co-workers, and legislators so that they can better understand this subject.

This excerpt from the “Establishing Realistic Speed Limits” booklet summarizes things well:

Contrary to popular belief, lower speed limits do not necessarily improve safety. The more uniform the speeds of vehicles in a traffic stream, the less chance there is for conflict and crashes. Posting speed limits lower or higher than what the majority of drivers are traveling produces two distinct groups of drivers: those attempting to observe the speed limit and those driving at a speed they feel is reasonable and prudent. These differences in speeds can result in increased crashes due to tailgating, improper passing, reckless driving, and weaving from lane to lane.

The key to improving traffic safety isn’t slowing everyone down, it’s getting drivers to travel near the same speed. This is something that the 85th percentile accomplishes naturally.

It may seem counter-intuitive, but it’s the truth.


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Speed Limits

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87 Responses to “Speed Limits: Slower Does Not Mean Safer”

  1. PMckrackin says:

    So when is the NMA going to stop censoring us and let the blog continue?

  2. Richard Mamches says:

    I just returned from a road trip I took last week on my vacation to visit my sister and nephew in northern Virginia. I briefly visited New Jersey and traveled on I-195, officially named as the James J. Howard Interstate Highway–in memory of the late, unlamented “Father of 55!” What struck me as ultimately ironic is that this highway is posted at 65 mph, along with most other New Jersey Interstates and toll roads. Congressman Howard, as we all know, fought for the “double nickel” and against higher speed limits tooth and nail in the later years of his life until his death in 1988. The so-called “Father of 55″ and chief advocate and spokesman for velociphobia must be turning in his grave over a highway in his memory now posted at 65 mph, which he so vehemently opposed.

  3. Phil Mckrackin says:

    Randy,
    No one cares because they have all been brainwashed by the NMA into thinking that faster is safer. You are correct Randy the key is having traffic traveling at like speeds. These knucklehaeds only hear what they want to hear they don’t care thet compliance with current speed limits would be just effective in reducing crashes because they want to drive faster not slower. The only reason that the 85th percentile speed has a safety benefit is because it is at the top of the 10mph pace(the 10mph area in the speed distribution that holds the largest percentage of the speed distribution.) meaning if speed limits are set at the 85th percentile or the top of the pace there would be a temporary safety benefit. However because these idiots don’t understand that faster is not safer they will then begin to exceed even that top of pace/85th percentile speed and degrade safety for all the lawfully proceeding vehicles. Compliance with todays speed limits would have a greater safety benefit effect on the speed distribution because not only will we get the benefit of having like speeds and the reduced crash rate associated with that but crash speeds would be lower and less Kinetic energy carried into the crash that would need to be dissipated by heat, friction and deformed matter. It really is too bad that these seemingly intelligent people are being mislead so by the NMA. I think it is laziness, they are too lazy to check the so called facts held within the articles that the NMA presents to them.

  4. MW says:

    Randy; Randall…surely a MN Highway Patrol who has asserted that those for Constitutional government/taxes and rational traffic laws as “domestic terroritsts”. Go figure!

    • Phil Mckrackin says:

      I have a similar opinion of the NMA simply because of thier methodology of trying to force change by encouraging drivers to break traffic laws. The definition of a terrorist is : A person who systematically uses terror especially as a means of coercion.

      The NMA has been engaged in systematically convincing the public, through fear mongering, that traffic laws are not enacted with regard to thier safety and that they are at at risk of serious injury or death if they obey them. The NMA uses this tactic to coerce these motorists to not obey the traffic laws so that the system will be forced to change. It appears to me as it did to Randy that the NMA uses terrorism to scare the public into believing that they are in danger of injury and/or death unless they support the agenda of the NMA.

      I fully support the quest to insure that the government acts constitutionally. I am all for rational traffic laws but if you are asserting that the NMA is for rational traffic laws then you haven’t been reading any of the content on this site. I guess it would be a persepctive issue as to rational by who’s definition of rational. The government can not operate without collecting taxes. If by “for contitutional taxes” you mean no fines, you have been brainwashed by the NMA. Speeding is a violation of law as such anyone caught speeding can be imposed a fine to pay. I am going to assert that speeding violations are the only traffic law you feel is enforced for revenue since that is the stereotypical NMA view point. Only an idiot would not want drivers who have been convicted of driving left of center, DUI/DWI, stop sign & light violations, driving recklessly, carelessly, aggressively to be fined for thier non conformity to the desired and expected behaviors on the road. Since I am pretty sure you are not an idiot I will assert that you believe such violations of law should be enforced and carry a fine as retribution for said violation. That being said, How exactly does the issuance of speeding tickets differ as to the enforcement, adjudication and fines for said speeding violation? Where does speeding ticket fine money go that other violation fine money does not? Why don’t you give me some traffic laws that the NMA is fighting to make rational and what the NMA is proposing is a rational traffic law to regulate those behaviors and I’ll give you my rational perspective of how I think the behavior should be regulated.

    • Henry says:

      There is no shortage of cranks who would willfully regulate every aspect of daily life. When it begins to affect them, however, they will scream loudest.

  5. Phil Mckrackin says:

    Henry,

    Marc Green PHD a visual expert reports that a vehicle traveling at 35mph will need a minimum distance of 138ft to stop. He also reports that because of the constraints of headlamp design (headlamps can’t direct alot of light upwards or to the left into the eyes of oncoming traffic) the best headlamps project very little usable light beyond 100ft. I don’t know if you can grasp this concept or not but if the hazard is 100ft away and it takes the vehicle 138ft to come to rest you have driven over the hazard by 38ft. Marc Green goes on to say: “The key concept is “assured-clear-distance,” which refers to the distance ahead that a driver can see a pedestrian on the road. Most drivers are taught to drive slowly enough that they could stop for a pedestrian who just falls within their assured-clear-distance, otherwise they would be “overdriving” their headlamps. Some US states have even make this a matter of law; anyone who overdrives his/her headlamps and has an accident is automatically guilty. However, automobile headlamps provide such a short assured-clear-distance that even drivers who obey the speed limit are often overdriving their headlamps.”

    Marc Green PHD also goes on to discuss the contrast of the hazard within the lighting pattern. He notes that the low beams of a car provide usable light for only about 100ft. Then explains that shorter distances (within the usable light) are positive contrast areas while longer distances(outside the usable light) are negative contrast and at some point the hazard switches from negative contrast to positive contrast as the driver approaches and at some point the hazard must go through a period of zero contrast and be literally invisible.

    He also noted the following: “In one study, the average driver saw dark-clothed pedestrians standing “a foot or two” to right of the car at a range of 150 feet while 90% of the drivers fell in a range from 50-250 feet. When pedestrians stood the left, the visibility distances halved. Using some reasonable assumptions, the authors concluded that a driver traveling 55 mph would fail to see a pedestrian on the right in time to avoid collision 45% of the time. If the pedestrian is standing to the left, the number grows to 95% – the driver will almost always hit the pedestrian.”

    I know you are thinking “Some drivers saw the hazard at 250ft. so I will give you a quick math lesson. it takes 3/4 of a second for perception of the hazard 3/4 of a second for reaction to the hazard. So using your 70mph safe and comfortable speed would workout like this 70mph equals 102.62 ft/sec. 3/4 of a second you’d travel 76.965ft while percieving and then another 76.965ft while reacting. you travled 153.93ft before you applied the brakes. Now that you have applied the brakes the distance you will travel is equal to the square of your speed divided by 30 times the frictional coefficient between the roadway and your tires. Assuming .80 as a frictional coefficient which is on the high side (meaning you’ll stop faster) will give you a stopping distance after the brakes are applied of 204.16ft. so now you saw the hazard at 250ft away you traveled 153.93ft before the brakes applied and 204.16 after they were applied for a total of 358.09ft. you drove over the hazard by 108.09ft. If you were driving a tractor trailer there is and additional 3/4 of a second for the air brakes to engage so you’d travel an additional 76.965ft. If you reduced your speed by 5mph you would travel 71.4675ft while percieving, 71.4675 while reacting to the hazard. You traveled 142.935ft before the brakes were applied and then 176.04ft after you applied them for a total of 318.975. all that you have accomplished is reducing the distance you must walk back to see what you hit because this time you only drove over the hazard by 68.975ft. You reduced the distance you over ran the hazard by 39.115ft.

    In both of these examples I used 3/4 of a second to percieve and 3/4 of a second to react. Night time driving usually results in a slower perception and a slower reaction. typically 1.9 seconds versus 1.5(1.6 is the industry standard for traffic crash reconstruction under good lighting and good driving conditions). Note that poor lighting(night time driving) and poor driving conditions(weather, traffic, intoxication, ect) all contribute to longer perception times and reaction times meaning the example above is a best case scenario and it wasn’t favorable to your argument.

    • Henry says:

      Did you spend all day figuring this out? I will concede that this is interesting material. On the other hand, I’m sure that there are other factors that these calculations don’t take into account that will balance out my argument. The simple fact that accidents per 100 mvmt have been dropping for 40+ years bears out that improved lighting, better vehicles are a factor in allowing for increased speeds, day and night, still validate night driving speeds of 70 mph do not pose excessive dangers on controlled access highways.

  6. Phil Mckrackin says:

    Randy,
    Since Speed related deaths are 2nd only to DUI/DWI fatalities, what do you think would happen to the fatality rates if we enforced speed offeses as strictly as we do DUI/DWI?

  7. Phil Mckrackin says:

    Also with regards to your night time driving the 5mph reduction you take is likely not enough to prevent a crash. You need to slow at least 10mph from 70mph to give you enough time to stop within the light pattern of your automobile. That you don’t know this surprises me, especially since you claim that you drive safely.

    • Henry says:

      No accidents 29 years. Plenty of people drive above 70 mph at night without incident. It’s about using the car ahead of you to navigate the road as well. Lighting technology is far superior to what it was during the 1970s. Same with automotive brakes.

    • Phil Mckrackin says:

      That the increased risk doesn’t manifest itself into crashes doesn’t mean that over driving one’s headlamps is a safe behavior. The car ahead of you may not illuminate the hazard to you and if you are over driving your headlamps by the time your headlamps illuminate it, there will be nothing you can do but hit it. Even though lighting technology has advanced since the 1970s and automotive brakes have also advanced at 70mph you are over driving your headlamps. I will illustrate how when I have more time to write a detailed post. “No accidents 29 years” still leaves us without the entire story. Are you telling us your last crash was 30 years ago? How many years have you been driving? How many miles do you drive each year? That driving at 70 has not resulted in a crash is of no significant value. How many F1 drivers go years without a crash driving at 200 mph? does that rationalize we should all be driving at 200mph? That your risk level has not manifested itself into a crash doesn’t mean your risk level is low.

    • Henry says:

      Phil – you are attempting to split hairs here. I started driving 29 years ago. Besides, the validity of the so-called scientific references you cite don’t pan out in the real world. Since that is the world we operate our vehicles in, the laws need to reflect the behavior of a largely sane majority of people who drive at speeds they feel safe and comfortable driving, day or night. Is there value in a nightime speed limit? In some cases yes. How shoudl it be set? The same way day time speed limits should be set: according to the 85th percentile under free flowing traffic conditions.

  8. Henry says:

    There are some people with a whole lot of time on their hands to debate nonsense. As an accident free motorist for 29 years, when the speed limit was 55, my overall cruise speed was about 70-75 mph. The car I was driving was slow and underpowered. In 1987, I bought a new car in Jan 1987. I bumped my cruise speed to 80 mph. Three months later, when they raised it to 65 mph on rural interstates, I maintained 80 mph cruise speeds. Fast forward 20 years with 70 mph limits in my state and my speed is still 80 mph. Driving above that worsens the tradeoff between fuel economy and travel times for me.I will always continue to drive speeds at which I feel safe and comfortable driving regardless of the speed limit. During the whole time I have been driving, speeds have increased and fatality rates have dropped. Slower does not mean safer and speed does not kill.

    • Randy says:

      Henry you are brain washed by everything here. If you have been driving for 29 years you probably remeber when getting in an accident at 30 mph you had a good chance of getting killed. With the current cars your chances of getting killed at that speed if you have your seatbelt on is slim. All you and others care is that your death rate is not going up with increased speeds. Guess what, with the newer cars there should be few deaths. If you have about the same amount of deaths as there was 30 years ago there is something wrong because there should not be. Deaths are not as large of a significant statistic as it used to be though. With air bags and seat belts, head injuries causing death are down dramatically. Other injuries are now becoming a more significant number to look at.

      It is definitley not all about speeds and speed limits though. Drunken driving is still the most preventable way of reducing accidents and death along with things like cell phones and other distractions now. One thing I did read lately is that the high amount of drunken drivers that also speed. Each of those things compounds the other.

      You say you drive at 80 mph all the time now. I wouild like to know is it that you need to drive that fast all the time or is it a habit that makes you drive that fast? If you have to drive that fast how many miles do you drive each day?

      Are you one of those people that has to pass a person on a two lane roadway even if the other person is traveling a few miles per hour over the limit and you are within a mile or two of your destination. This is just something I have really noticed lately.

    • Henry says:

      Randy –

      First, miles driven have tripled over the last 30 years, so it is not that amazing fatalities are at 37,000 per year. They haven’t been that low since 1963. Fatality rates have dropped from 3.5 deaths to 1.3 deaths per 100 mvmt. In addition, overall accidents have dropped as well. Safer cars do play a role in that.

      I am safe and comfortable at 80 mph. I drive that speed on limited access roads. On two lane roads, I drive slower. If I pass on a two lane, I do it when it is legal and where there is maximum visibility. On a straight two lane, I usually cruise at 70 mph. At night, I cut my speeds by 5 mph or more.

      Let’s turn the question around. How fast do you drive? Why do you care about how fast I drive? Are you one of those who drives under the speed limit on two lane roads and lets traffic back up behind them? What do you think the speed limits should be?

      I can’t believe I’m being sucked into this topic.

    • Randy says:

      Henry if there is traffic on a two lane roadway I drive the speed limit or a little more if I have people behind me so they do not make it unsafe for others passing. If I am driving on a two lane roadway with almost no traffic I often leave 5 minutes early and drive under the limit when no cars are behind me and my gas mileage soars and like the other night when a deer was on the road in front of me I had time to slow down to let it finish crossing the road . That would be unheard of by you. People like you leave 2 minutes late for something so you have an excuse to drive well over any limits. I have learned that people like you are stupid because you pass any time you can lawfully do it and sometimes others even do it in no pausing zones. This is sometimes only to drive 5 mph faster and many times only saves 5 seconds to 30 seconds of travel time. If you think it is smart to pass other vehicles just because you can is stupid and increases the chance of something bad happening many times.

      I have also seen that many of you so called fast drivers also are the major violators of tailgating which is a major contributor of multicar crashes. Also fast drivers over drive their headlights. You said you drive 75 mph at night. You have to have your bright headlights on at that speed to see anything in front of you. You say that you have driven accident free driving 80 mph all the time. That may be true but people can drive fast on snow packed roads also until eventually they go in the ditch.

      I have done a lot of analysis of the way surrounding people drive. People for the most part do not drive fast because they need to like you said. It is because they are used to doing it. People like most on this site will drive a little faster every year and as long as they do not have an accident they feel very safe. The fact is that the faster you drive if anything happens that would cause and accident that accident will be a lot worse driving fast. Driving fast on a straight low traffic volume road would cause little chance of accidents or putting others in danger but driving fast in heavy traffic along with tailgating is stupid.

    • Randy says:

      Henry one thing I left out is that DUI is one of the major reasons for car accidents and fatalities. That information is often left out on this site particularly when you and others bring up that accident rates and fatalities are lower. Yes the cars are a lot better and safer but also the DUI laws and significant enforcement have both contributed to bringing down the numbers of accidents caused by DUI. Most here do not believe that enforcement of DUI has done anything but they are wrong. They bring up the fact that many people are arrested many times for DUI. That may be true but there are millions of people out there that make sure that they do not drive when they have had too much. They do not want to face the consequences. In many states you also have to put interlocks on your car if you have been convicted of DUI so that you do not drink and drive.

    • Phil Mckrackin says:

      You are partially correct Henry slower is not necessarily safer. The part you are missing is that faster is not necessarily safer either. Neither can be measured to be safer if you measure the manifestation of risk and not the actual risk itself. You can’t measure risk by lack of simple crashes if you are measuring safety by how many casualty crashes occur. You are using apples and oranges. You are either intelectually dishonest or as Randy suggests, brainwashed by the NMA. The NMA originated the phrase “speeds are up while fatalities are down” as part of thier propaganda campaign to drum up additional support from those who really don’t have a clue. The statement appears on it’s face to be true and supported by data. However, what the statement doesn’t say is that fatalities are down as a result of speeds being up. If the statement can’t say that truthfully the two individual ideas held within that statement cannot be correlated. which makes it an obvious attempt to decieve. Now onto your other claim that speed does not kill. It should read speeding does not kill, because the act of exceeding a posted limit doesn’t necessarily manifest the increased risk into a crash. However, as I mentioned earlier you the NMA measures risk of casualty crash with the risk curve of simple crash, which is again intelectual dishonesty. Why would they purposefully mislead you like that? Because if the showed you the risk curve for casualty crash as studied by O’Day and Flora (1982), Joksch (1993) and Kloeden et al. (1997) you would clearly see that the risk of casualty crash increases as a function of speed. The NMA would like you to believe that the risk of simple crash is all that determines safety and that there is no need to consider the severity of the crashes that do occur. Since you can’t eliminate the risk of crash totally, there will always be crashes and the severity of those crashes is an important issue. “Clearly, a research or engineering approach to speed management that ignores the injury consequences of vehicle speed could lead to unintended results.” That you have a 29 year crash free experience has no correlation to your travel speeds and is no indication that you were in a low risk area of the speed distribution. What it indicates is that your risk level never manifested into a crash. Nothing more nothing less. I also note that you have taken classes from the NMA on how to phrase your statements. Lets examine what appears to be an original thought that you expressed: “As an accident free motorist for 29 years, when the speed limit was 55, my overall cruise speed was about 70-75 mph.” I notice you didn’t qualify your 29 accident free years as consecutive, cumulative or total. You didn’t tell us if you have been driving only 29 years or 50 years. We have absolutely no way to weigh your statistic and it is therfore irrelevant here in this conversation. Lets examine another of your claims: “I will always continue to drive speeds at which I feel safe and comfortable driving regardless of the speed limit.” This is not an idicator of your driving being safe and all it really proves is your blatent disregard and disrespect for the law. You propably should have indicated here that if speed limits were set more appropriately you would comply with them. Without that simple disclaimer all you really are is an unlawful motorists and frequent violator.

    • Phil Mckrackin says:

      Henry((First, miles driven have tripled over the last 30 years, so it is not that amazing fatalities are at 37,000 per year. They haven’t been that low since 1963. Fatality rates have dropped from 3.5 deaths to 1.3 deaths per 100 mvmt. In addition, overall accidents have dropped as well. Safer cars do play a role in that.))

      Phil((In 1968 fatality counts were over 50,000 each year. after the 1973 NMSL they dropped into the low 40,000 area and remained there until drivers started to return thier speeds to what was normal before the NMSL(they were speeding up) at which time the fatality counts peaked over 50,000 once again. Technological advances in automobile design and better roadways have contributed to reducing those fatality counts down to 34,017 in 2008. And I beg to differ on your assertion that the fatality counts have not been below 37,000 since 1963. In 1994 the national fatality count was 36,254 so although you write with authority and pretend to know you really are just mimicing what the NMA tells you(I have seen other NMA members spout out those same stats that you just did, albeit incorrectly).))

      Henry((I am safe and comfortable at 80 mph. I drive that speed on limited access roads. On two lane roads, I drive slower. If I pass on a two lane, I do it when it is legal and where there is maximum visibility. On a straight two lane, I usually cruise at 70 mph. At night, I cut my speeds by 5 mph or more.))

      Phil ((You may well feel very comfortable on limited access roads at 80mph. However, 80mph is not always safe on every limited access roadway. You apparently have little respect for the law so I don’t understand why you would make sure you pass only when it is legal. You haven’t qualified when you will cruise at 70mph beyond that the 2 lane roadway was straight, there are many other factors that determine safety other than if the roadway is straight. That straight is the only criteria you list I envision you do not take into account things such as # of intersections, # of driveways, bicycle traffic, pedestrian traffic roadway width and pavement width. Which leads me to stand by my original assessment that you are nothing more than an unlawful motorist who rationalizes his behavior with the rants of a grass roots organization that propagandizes that his behavior is acceptable.))

      Henry((Let’s turn the question around. How fast do you drive? Why do you care about how fast I drive? Are you one of those who drives under the speed limit on two lane roads and lets traffic back up behind them? What do you think the speed limits should be?))

      Phil((I am not complaining that the limits are under posted so my speed is not the issue. If you are going to complain that the law is wrong you’ll have to do a better job of convincing me than you drive faster than that which is defined as lawful. That isn’t anything more than the sour grapes syndrome. If you can wait to pass until it is legal why is it you can’t choose a legal speed? BTW compliance with the law will make speeds around the speed limit the safest place to drive. That you degrade safety for yourself doesn’t concern me. However, that you degrade the safety of others and call it your right is very compelling evidence that supports my assessment that you are little more than an unlawful motorist.))

      Henry((I can’t believe I’m being sucked into this topic.))

      Phil((you can stop at anytime!))

  9. Phil Mckrackin says:

    Quote from article above “Contrary to popular belief, lower speed limits do not necessarily improve safety. The more uniform the speeds of vehicles in a traffic stream, the less chance there is for conflict and crashes. Posting speed limits lower or higher than what the majority of drivers are traveling produces two distinct groups of drivers: those attempting to observe the speed limit and those driving at a speed they feel is reasonable and prudent. These differences in speeds can result in increased crashes due to tailgating, improper passing, reckless driving, and weaving from lane to lane.”

    The more uniform the travel speeds of the traffic stream the lower the chances of crash. This does not equal “we must increase speed limits” as the article above implies is the only solution. If instead of condoning unlawful behavior the NMA supported and suggested compliance to the posted limits and said compliance was gained the roadway would be just as safe through adjusting the 85th percentile of the traffic stream down. I am all for correcting speed limits even if that includes increasing speed limits. I am however, against the practices of the NMA and thier members of suggesting increases and only increases are what provide safety that is a lie. I am also against the practices of the NMA and it’s members to try to secure future speed limit increases after the limits are corrected to the top of the pace. Parker said that “the greatest safety benefits are accomplished when the speed limit is posted within 5mph of the 85th percentile”. although the article above doesn’t recognize this or that there are other important factors that need to be considered beyond what the 85th percentile speed is. Almost all venues in America USE the 85th percentile speed as a starting point when setting speed limits. The problem with using only the 85th percentile speed to set the speed limits is that it rewards drivers for acting unlawfully. It also uses the false perception that most drivers drive in a safe and sane manner. Drivers can drive at what they percieve to be a safe manner that really isn’t as safe as they think. To exhibit this point I will direct your attention to scenarios where drivers ignore (or percieve incorrectly) thier stopping distances or sight distances. 1st scenario is traffic in NJ or Michigan where the flow of traffic is 70+mph and you are in almost bumper to bumper traffic, This is an example of how the driver incorrectly percieves he has enough room to stop from that speed if he needs to. 2nd scenario is night time driving where the driver can only see to the extent of his headlamps illumination. Most drivers at night have no problem choosing to exceed 70mph which is a speed at which they are overdriving thier headlamps. If 85% of drivers can’t get these scenarios right what makes you think that thier perception of travel speed would be any better. The only advantage to posting to where 85% of the traffic chooses to drive is uniformity in traffic speed as noted above. A side benefit is a “temporary” increase in compliance. I say “temporary” because the NMA and it’s members insist on there being a grace speed above any posted limit . If that posted limit is set at the 85th percentile allowing 5mph above the limit allows 2/3 of the 15% that is defined as unlawful to proceed without experiencing enforcement actions. If we allow another 5mph above that(which is what is current practice in most venues 10mph) you have defined or allowed almost the entire traffic stream to proceed both lawfully and unlawfully without any enforcement. How long will drivers comply to even an 85th percentile speed limit if they know that they will not experience enforcement upto and through the 98th percentile speed? Again I am all for increased speed limits derrived from the top of pace speeds. I am unfortunately not in agreement with the NMA or it’s membership that simply raising speed limits is the answer, The problems with our current system are much deeper than where the limits are set. Lower speed limits do not necessarily improve safety and higher speed limits do not necessarily improve safety either. Without addressing the other parts of our system that need reform it would be a huge mistake to increase all speed limits to the 85th percentile. Incidentally Parker acknowledged that not all speed limits should be raised in response to his work and cautioned within the text of his 1992 & 1997 report.

    • James says:

      OMG, learn to use paragraphs.

      You would be correct, except: Most people won’t do what you tell them to, otherwise they’d follow the speed limits. The majority of people will drive at whatever speed they feel safe. By setting the speed limit at the 85th percentile, those who drive at the speed limit will drive at the same speed as those who drive where they feel safest.

      Secondly, the speeds won’t increase if the speed limits are appropriately set – if a highway was 30mph and they increased it to 40, yes, everyone would drive 10mph faster, because they are only not driving 70mph to avoid being arrested. But if the speed limit was changed to a reasonable one, average speeds are not likely to change. On one road that was recently studied, adjusting the speed limit up 10mph to the 85th produced a change in average speed of 1mph.

      Drivers do not “comply” with an 85th percentile speed limit. You have the entire idea reversed in your head. The 85th percentile speed limit complies with how fast drivers would choose to drive – which is to say that 85% of drivers would comply with it even if they weren’t punished for breaking it.

      And you can’t declare an entire idea a bad one because it doesn’t work for every road. That’s like saying drinking milk is bad, since some people are lactose intolerant.

    • Randy says:

      James you believe the NMA propaganda just like most here do. You say drivers drive as fast as they feel safe to. Yes that can be true but if you are driving in a residential area it does not matter how safe you feel driving the speed is set so that others are safe from you particularly kids.

      You say that increasing speed limits has shown not to increase vehicle speeds. That is true when there was no one making them slow down in the first place. In other words if no one was reading the signs or stopped if they were not following the signs there should be no difference in speeds if the signs are changed. There is also often more enforcement on a road after the speed limit is increased to make sure that people do not increase their speed over the new limit. This is often the case and documented by many news stations.

      You say the 85 percentile speed is the answer to safety. People get used to driving fast. They do not realize any danger in it until they do lose control or hit someone. If you do not believe me read my posts from October 10th futher down this page that had the links. Go to those links.

      I have read about one area that was setting the limits in a scientific way. They first went by the 85 percentile rule and then they slowed down the limits on the roads that had problems where people should be driving slower. Some of the things were no shoulder on the road, visibility problems and multiple access areas to the highway and much more. What this says is that it does not matter how fast people think they can drive safely they should be driving slower in certain areas and roads.

    • Phil Mckrackin says:

      OMG, learn to indent your paragraphs! OOOPS, guess it is a problem with the blog program. I did use paragraphs but if you don’t leave an additional line space the program bunches your paragraphs together just as it loses the indent of the paragraphs. It is an informal blog so don’t expect that I will pay much attention to your mindless attacks on my posting methods, what I am here for is the content

      I am correct, with no exceptions. Most people will drive as fast as you let them drive. I believe thier perceptions of what is safe is faulty and over ruled by thier desire to drive where they are comfortable, which is a product of many things including thier saving time. I gave two examples of where reasonable drivers make faulty decisions of travel speed and/or do not consider things they should be considering to make a good choice of travel speed. Setting the speed limit to the 85th percentile level is only part of what needs to be accomplished for it to work as you portray it as working. I am not against raising speed limits. I am against raising speed limits too hastily or without consideration for how the raises will effect driver’s behaviors.

      I sort of understand what you are asserting when you say “the speeds won’t increase if the limits are appropriately set”. When you say they won’t increase, you don’t mean they won’t increase at all, you mean that the 85th will increase with limits 1mph for every 5 of the increase. I understand how someone with your agendas would see that as not statistically significant and you have chosen to say it doesn’t happen even though it does happen. Reality of it is that it does happen and I have two issues with it happening.1) In order for the 85 percentile speed to move 1mph portions of the traffic stream must move alot more than 1mph. 2) changes as small as 3 mph in the 85th have been proven to exponentially increase the severity of crashes, even though that science isn’t the science you are referring to when you say you want the limits to be scientifically set.

      With respect to your thoughts on compliance I respectfully disagree with your assertion that I have it revesed in my head. In order for any speed limit to provide a safety benefit the motorists must comply with that speed limit and become a part of the pace. simply reposting the speed limits to redefine everyone as compliant will not work because soon the motorists will adjust thier behaviors to match the new speed limit and there is no way that reposting a speed limit to the 85th percentile will magically get compliance if violators did not experience enforcement actions. The only reason that 85% of drivers are compliant with a speed limit posted at the 85th percentile is because by definition of the 85th percentile they are at or below that speed already. The reason I said “temporary” is because that compliance is only temporary until the motorists adjust thier behaviors to the new speed limit. What I am trying to get you to understand is that along with a reasonable speed limit we need a reform of enforcement policies and practices. If you repost a speed limit to the 85th percentile speed and allow 5mph above the 85th percentile before you start issuing citations then your new 85th will be closer to the old 85th+ 5mph than it will be to the original 85th. I have seen you NMA lifers say it many times t”that you can’t expect motorists to comply with a speed limit that they don’t percieve as a valid speed limit”. If you allow 5mph over the 85th percentile speed limit you have already doomed that speed limit to failure, because the motorists will not percieve it as valid if some of those defined as unlawful get a pass because of a grace.

      I have not declared the idea of posting speed limits at the 85th percentile speed as bad, because it doesn’t work on every roadway. I just realize that not every roadway will benefit from an 85th percentile speed limits, so I believe we should be careful while reposting speed limits to that level. I Prefer the top of pace area for posting the limits because I believe it is a truer representation of what is happening within the traffic stream than the 85th percentile speed is. I also realize in many situations that the 85th percentile speed or top of pace speed will result in the same limit being posted. What I am declaring a bad idea is the unthought through methodology of reposting the limits to the 85th that the NMA and many of it’s members are citing as the end all method of posting speed limits. I believe that methodology has the potential to bring forth many unintended results. The reposting of speed limits to a corrected level, be it the top of pace or the 85th, needs to be accompanied by enforcement reforms that make the new speed limit known as the maximum safest speed allowed. Without enforcement or the perception that the number on the sign is the maximum safest speed allowed all you will accomplish is a change of numbers on the signs and you will have accomplished nothing in the way of safety. You will have moved the safest point of the speed distribution upward along with the limit. The new limit will become set at below the 50th and the NMA will still be needed to fight to get this corrected with another speed limit increase.

    • James says:

      Thanks for the paragraphs, it makes it a lot easier to read!

      By and large, I agree with most of what you are saying, however, you say: “people will drive as fast as you let them drive.” – which simply isn’t true. Go out after a snow storm, or even during a severe rain storm – people are not driving at the speed limit, because that’d simply be too dangerous. Likewise, if you go to a sharp turn on a rural road, people will not take that turn at the speed limit, or even at the limit imposed by physics, but will slow down in order to take it safely.

      I was speaking of statistics, not science. I know that energy (and thus severity) of a crash is exponentially related to speed, but with the improvements in automobile safety a crash at 85mph today is safer than a crash at 55mph during the 1970’s.

      If the 85th moves up 1mph that is much more likely to the traffic that obeys the speed limit moving up 10mph than the traffic that ignores the speed limit driving faster. In fact, if we say a quarter of the traffic obeys the speed limit, then that means that the rest of the traffic actually slowed down. Speed differentials are down, and the traffic is much safer.

      As for your final point, I would strict enforcement of *reasonable* limits would improve safety on our roadways.

    • Randy says:

      James the only problem with your statement is that you say that people slow down when there is snow on the pavement. That may be true if the speed limit is 85 mph because they would be off the road within minutes. That is not true that they slow to a safe rate of speed. If that was true there would only be one or two cars in the ditch ever on the road rather then the ome pr twp dpzem you sometimes see in the winter. I have driven in Colorado in the winter and saw how fast cars drive with snow on the road. They think they are safe with 4 wheel drive. You then hear on the radio where there were multicar pileups on the passes. This is a fact that they are driving too fast.

      You are also true that cars are much safer than they were 30 years ago. That does not mean that we have to try to keep the death rate the same. It should go down a lot if cars are safer.

      You say to increase the speed limits a lot to increase safety so that everyone is driving the same speed. I have news for you, there are many large vehicles that do not drive over 60 or 65 mph no matter what the limit is. If you increase the limit you are telling others to drive a lot faster than these slower vehicles. That is one of the main reaseons so many people are going over the limit today. They need to pass the slower vehicles but are intimidated by other drivers like the ones from this site if they are not driving 80 mph or higher in the so called fast lane.

    • Phil Mckrackin says:

      You are welcome for the paragraphs. It was not my intent to bunch the whole thing as 1 paragraph but if I type normally and only hit the return key 1 time at the end of a paragraph the blog program bunches everything, note above it did it again with my response to Henry.

      I disagree with you on “people will drive as fast as you let them” issue. Snow storms are an example, people don’t slow down for snow unless they actually see others crashing or sliding. 4×4 owners think that with 4 wheel drive traction to get you moving also comes better traction for stopping and very rarely slow thier travel speeds. Night time is another example, if you are traveling at night time on an unlit interstate at above 70 mph you are over driving the headlamps. In MI I see traffic 75mph with less than 1 car between vehicles as a common occurence. there is no way they can stop from that speed in that small of a distance without a collission.

      If you over post a sharp turn or roadway with many various turns, accident experience increases. This happened in TX where a roadway was simply increased to 70mph because of it’s class of roadway status and it resulted in a very high increase in accident experience. until they figured out why and reduced the speed back down.

      Thank you for your support on the final point of strict enforcement of reasonable limits. The NMA vigorously opposes that mindset because thier goals are not genuinely safety, they want speed limits to increase as high as possible and they want no enforcement.

  10. Randy says:

    Roundabouts were just on TV. It talked about how much safer an intersection became because it became a roundabout. Many deaths occurred before the change was made and now none. It is a pretty simple concept. Have everyone slow down a lot and look for the other guy and there are no major accidents. That is a big change from someone speeding up to well over the speed limit to try to beat the light and miss by 2 or 3 seconds.

    • James says:

      And its not possibly because of better traffic flow?

      Which is exactly what the article you are posting in response to is in favor of?

    • Randy says:

      James, I have no idea what you just said. I was commenting on what the news show had on tv about how safe Roundabouts are. If you are saying that they would not work very well with very high volumes of vehicles you are probably right.

  11. Phil Mckrackin says:

    Here is an editorial article that the NMA published in July/August1996. What I’d like you to take note of is the section called “cushion” The author of this article writes as if he is an authority on this subject and makes certain assertions about why The National Highway Traffic Safety Administration recommends that you leave a two-second cushion between your car and the one in front of you. He even tries to mathamatically solve the problem which only needs very basic algebra to solve. His math is entirely WRONG. 60mph is 87.96 feet per second, Not a major mistake but the author rounded up when the proper mathematical function should have been to truncate. His 1st mathematical error leads directly to his second if he hadn’t rounded he would have been able to have the correct following distance of 175.92 ft. From here on out it is all down hill. What does happen if the guy in front of you hits his brakes. it takes you 3/4 of a second to percieve the tail lights and another 3/4 of a second to react this is a bright sunny and clear day where the driver is alert and not intoxicated. Night time and poor weather add time to this an does driver inattention and possible intoxication. so the simple 1/2 second he quoted is actually more than 1.5 seconds. Traffic Crasgh reconstructionists use a standard perception/reaction time of 1.6 seconds for favorable conditions and 1.75, 2.00 & 2.50 for increasingly less favorable conditions such as night time and intoxication. If the conditions were favorable you’d have traveled 140.736 ft before the brakes actually applied and approximately 153 ft to stop on and average dry roadway surface with no grade. so your car will travel approx 293.736 ft from the point where you see the tail lights of the car in front of you light till your car comes to a complete stop. The author incorrectly asserted that there would not be enough room between you and the vehicle in front of you if it only took you 1/2 second total to percieve and react to the tail lights. because he incorrectly assumed that the point where the tail lights lit was the final resting point of the vehicle in front of you. It would not be! If we assume the vehicle in front of you was also doing 60 mph he would stop approximately 153 ft further down the roadway. Meaning when both cars came to rest there would be a space greater than 35 feet between them. This two second cushion leaves plenty of space between you and the vehicle in front of you. In the authors haste to discredit NHTSA he assumed way too much and wasn’t familiar enough with the subject matter to do anything more than look like an idiot to those who understand this science. If the author made this many errors in this simple example how can you possibly trust anything he advises as being correct. The 35 ft would would be an additional .4 seconds which means that under 2 of the 3 less favorable perception/reaction times I listed above would yield enough room provided you were alert and attentive while driving. If the NMA publishes blatently incorrect content such as this how can you trust anything they publish to be correct? I have read many of thier articles and written many criticisms of them but unfortunately the point that they need to pay attention to details and check facts before publishing the articles hasn’t made it to thier heads yet. Instead they waste their time trying to discredit my constructive criticisms. My only goal as a contributing member of this blog is to have factual and correct content in the articles offered as facts on such an important subject matter.

    How to Drive Safe, Avoid Tickets, and Save Money
    Robert B. Henn
    ——————————————————————————–
    Safe driving is far more than taking a course in driver education; it’s also a matter of using your head and common sense.

    Time
    The first thing to fix firmly in your mind is that your sense of time goes out the window the moment you get into a car. This can easily be illustrated by timing how long it takes to get out of a side street onto a well-traveled road, and then asking someone else in the car to estimate how long you were sitting there. If you actually waited ten seconds, the other person would probably say 30 or more seconds.
    An example of this foregoing point is that if you leave late and try to make up some time by driving extra fast to work, you may save two or three whole seconds. Conversely, if you leave two minutes early, and try to spend some extra time by driving slowly, you’ll get there about two minutes early; perhaps one minute and 56 seconds early, if you really drag your feet.

    Another point, which you can prove for yourself quickly, comes from watching the progress of somebody who has passed you because of his feeling that you’re going too slowly. Pick out a marker when that person passes it, and count the seconds until you reach it. Somebody really steaming down the road will pick up as much as five whole seconds in a mile, and maybe even 30 seconds in a trip of five or ten miles. Big deal.

    Learning to drive
    The worst driver is one who is convinced that he’s the best driver in the world. So if somebody says “Wasn’t that last corner a little fast?”, consider if the remark was legitimate. If it wasn’t, forget it; if it was, learn from it.
    Continually analyze your own driving: “Did I make that entry onto the freeway properly, or did I almost risk an accident because I jumped into traffic too quickly?”

    Cushion
    The National Highway Traffic Safety Administration recommends that you leave a two-second cushion between your car and the one in front of you. Simple math: at 60 mph, you’re traveling 88 feet per second. Two seconds puts you 176 feet behind the guy you’re following. What happens if that guy hits the brakes? It takes the average driver one-half second to see the brake lights, conclude that the vehicle in front is slowing down, move the right foot from the accelerator to the brake and depress the pedal. You have already traveled 44 feet before your brakes even start to slow you down. Now you have one and a half seconds and 132 feet of maneuvering space left and you don’t even know what’s going on. All of this assumes that the pavement is bone-dry, there’s no other traffic to worry about, your brakes are in top condition, and your attention is directly on the brake lights of the car in front of you. To me, that two-second cushion doesn’t leave much room for error.
    Always allow for as much space as possible. Don’t drive directly behind or next to anyone when it isn’t necessary. This all pays off when someone has a slight emergency. You don’t get caught in it—you have enough room to use your brakes, swerve out of trouble, or just continue driving.

    Brains
    The best driver is the most alert driver–the one who is watching traffic, road conditions, driver behavior, external influences, weather, visibility, the condition of his own vehicle, and is continually assimilating that information.
    Money
    Just paying attention to these tips can save you lots of money on insurance costs, tickets, and body work (your’s and the car’s). Maybe it’s worth working on.

    ——————————————————————————–
    Source: July/Augest 1996 NMA News
    ——————————————————————————–

    • Randy says:

      I know that the 2 second rule is what is taught as a minimum but many drivers training courses tell you to leave at least 3 seconds of space between cars if at all possible. I find that particularly driving on a normal 2 lane roadway that is not limited access that I try to leave at least 5 seconds if there is little traffic so I do not have to constantly be accelerating and braking for the cars turning in front of me. The fast guys normally leave about 1 second in such driving conditions and their brake lights look like a flashing red stoplight being constantly on and off.

      Most here say the 2 or 3 second rule is bull though because they say that people should not be hitting the brakes or stopping for any reason on an interstate. They blame the person in front for such accidents.

    • Phil Mckrackin says:

      Of course the 2 second rule is an absolute minimum, the more space you leave between you and the car in front of you the less likely you are to have a conflict with him. Free flow traffic is measured at 4 second headways if there isn’t 4 seconds between the cars they aren’t considered free flowing.

  12. Phil Mckrackin says:

    Germany is not introducing speed limits they have had speed limits for a very long time. However, less and less of the autobahn is limitless some of the autobhn has speed limits and where there is not posted speed limit there is a suggested speed of 130kph. If you crash at a speed greater than 130kph you are financially responsible for the cost of the crash.

    • Doug says:

      Bull! You are partially responsible for the crash – how responsible depends upon the situation.
      In some areas less Autobahnen are limitless but other areas have introduced electronic signs which can be turned off. The A6 out of Stuttgart used to have a posted limit of 120Km/h but now with the electronic signs the limit can be 100, 120 or nothing.
      Most new Autobahnen in the former East are unlimited for greater distances than in the former West.

    • Randy says:

      Doug how many miles do you have to drive each day? Is it a need for you to drive 160 kph or do you just use it for your amusement?

    • Phil Mckrackin says:

      Doug please check the facts from someplace other than the NMA you’ll be surprised to how much of what the NMA tells you as fact is actually only propaganda. Here is a website that outlines Germany’s rules of the road for international travlers:http://www.gettingaroundgermany.info/regeln.htm#gen

    • Randy says:

      I had to laugh at that las link. George wants to move to Germany where anything goes. This is what the link said HaHaHa:

      Beware of enforcement cameras. Germany probably uses such cameras more than anyone else (except possibly Britain). Automatic cameras are stationed to catch speeders, red-light violators, and tailgaters. Sometimes an obscure sign will warn you of the existence of such a camera, but it’s usually too late by then. You’ll sometimes spot temporary cameras setup along the side of the Autobahn or on an overpass watching for tailgaters or speeders. Tickets are mailed to the registered owner of the vehicle within a few weeks

    • Doug says:

      I suggest you read the Web-address you listed again (Autobahn Section under Speed Limits). Its says exactly what I said.

      Of course I enjoy driving fast – as do most Autobahn drivers. Driving fast keeps us alert and makes us better drivers. The proliferation of bad drivers in France, Netherlands or Switzerland confirms this. When someone likes doing somethng, he does it better. I think any sport involving a ball, stick or puck is stupid and I suck at playing any of them.

      Germany doesn’t even come close to the enforcement cameras of Switzerland or France. Try driving to Zürich or the Loire Valley and see what I mean. Like in the US, only the Police are exempt from these limits (sometimes passing vehicles at 40Km/h over the Limit). At least German authorities are subject to the same traffic laws as everyone else. Cameras also prove guilt. Unlike the US, a cop can’t say you did something and you must prove your innocence. In Europe, you are innocent until proven guilty – period! No picture or video – No violation.

      In Germany, fixed or mobile cameras are nearly always in 100Km/h or less areas.

      By the way, I don’t take everything the NMA as gospil. I totally disagree with their stance on Drink Drive laws and I was very, very upset when they did nothing more than complaine a little about the the Montana Speed Limit and the following year’s 100% increase in deaths (I called as well as wrote NMA urging them to request Manslaughter charges against the Governor and others involved in passing the Speed Limit). In fact, the Montana Speed Limit was the deciding factor in my moving out of the United States.
      I know of no other democratic Country (well, maybe Canada) which places corporate and political greed above everything else.

    • Randy says:

      Doug driving fast is lame. Try racing on skis once because you do not put others at risk because the course is roped off and you can pull more Gs than in any car. If you still like to drive fast in a car open up race tracks for the armatures like yourself. The driving fast just for fun is not going to happen in the US if anyone in authority has anything to do with it. You say that Montana’s death rate went up after they put on their speed limits again. Do you know why all those deaths happened? In a state like Montana which has very few people anyway if you have a year with bad weather you can see increased deaths. Tell us why there were more deaths if it even happened.

      Driving fast just for the fun of it is stupid if you are putting others in danger . If you ever kill someone I hope they do not just throw you in jail but I hope that they torture you the rest of your life.

    • Randy says:

      Doug, I read about death statistics in Montana. You are right that some of the lowest death rates was between January and May of 1999 when there was no limit. I am sure that since you lived in Montana though that January through May is not the fast driving months of the year for a state like that. Often the roads are not good enough to drive fast in those months and the major contributor to accidents besides driinking is ice on the road in those months which is highly variable in accident statistics. You are an idiot to bring up such biased and meaningless staticstics. If you look at the full year statistics of deaths they did not double and depending on the year went up or down each year. There are few deaths in that state and there are many fluctuations. A report that I read said the major causes of accidents are drunk driving particularly because of the indian population and also the high amount of pickups that are very unsafe in accidents and have many roll overs. The report that I read also said that little can be determined from death rates in that state because there are so few but a better determiner is the injury rate.

    • Randy says:

      Another thing that I noticed with my research was the report that you must have been referring to. It did not match up with the facts. The report presented by NMA was wrong and mostly made up. The accident statistics and the seat belt use among other things was wrong but this is mostly the case of all NMA reports that they write.

  13. Doug says:

    Germany is NOT introducing Speed Limits! A 120Km/h Limit is being pushed by the Left (Communists) and Greens (practically Communists) but the ruling parties have rejected it. Speed Limits have been rejected time and time again because repeated claims about increased safety or a better environment have always been proven false.

    More Electronic Speed Limit signs are being installed which set speeds according to traffic conditions. These signs usually range from 100 -120Km/h but there are many which set the limit of 130. And I have seen the signs near Hannover set at 140. These signs are also switched off when conditions permit which then allow drivers to decide their own comfort level.

    If someone is driving over 130Km/h and is involved in an accident, he can be held partially at fault but studies have shown that the most Autobahn accidents involve drivers traveling 120Km/h or less while those traveling over 160Km/h are involved in the fewest.

    You couldn’t pay me $500, $5000, or $50.000 to move back to the US. I put up with its corrupt traffic enforcement system and incompetent drivers for too many decades.

    • Randy says:

      I am glad you are there also doug. The intelligence you have none of is best kept over there. It would be my guess that the vast majority of people travel under 160 kph and slower speeds are also more likely when the traffic is heavier making it much more likely to create an accident but people like you do not have enough brain power to figure that out. I forgot to say you are an idiot to bring that up.

    • Phil Mckrackin says:

      Doug,
      Put the number of crashes at 120kph and 160kph into a ratio ofdrivers in that speed category. What I believe you’ll find is that a larger percentage of the drivers doing 160kph are crashing as opposed to those only traveling 120kph. It may be fewer by number but not by percentage of drivers in that category.

    • Randy says:

      Phil, Doug like most from this site and also NMA bring up statistics that sound good on paper but if you look at the true facts and reasons behind the staticstics and the things that are left out they would be terrrible numbers.

    • Randy says:

      Video of George driving to work.

      http://www.youtube.com/watch?v=RZfczrgERXk

      Sorry. This is the video of George driving to work.

      http://www.youtube.com/watch?v=KbdH-J6UoYI&NR

    • Phil Mckrackin says:

      I know Randy! It isn't all thier fault though they do get bombarded with propaganda from the NMA. If you read the articles that are written by the NMA members on this site there are errors in almost all of them. Then when someone who knows points out those errors everyone hates him even though he has many common goals with these people. The amount of misinformation that is provided as fact on this site is a testimony to you can't believe everything posted on the internet. What annoys me is that with very little effort most of these lies and propaganda are obvious, so most are too lazy or too dumb to find the truth.

    • Randy says:

      Doug this thing does not happen around me where very very few drive over 75 mph.
      http://www.youtube.com/watch?v=EitmqUwtukc

    • Phil Mckrackin says:

      Randy I am sure you know why there are tents up at that scene. However I am sure the rest of the “lets drive as fast as we can club” has no clue that the tent is for a command center because there are more than 5 dead. looking at the scene I’d say possibly 10.

  14. George [C] says:

    ‘Good people do not need laws to tell them to act responsibly, while bad people will find a way around the laws.’

    The laws of physics apply equally well on all continents.

    • Randy says:

      Yes George and that is why many of the other continents are adding speed limits. You posited it yourself that Germany is. They found out that they need to control people like the ones that post here that are not out to drive to get somewhere but to try to be armature racers and usually bad ones at that.

      Will $500 be enough to help move you to another continent?

    • George [C] says:

      What are you talking about? $500

    • Randy says:

      To help move you to Europe.

    • George [C] says:

      Not me, somebody else.

    • Phil Mckrackin says:

      Since you mentioned the laws of physics George. why is it that the NMA does not consider that Kinetic Energy that must be dissipated in a crash increases by the square of the speed of the vehicle. Why do thay also use the simple crash curve to mislead the readers into thinking that speeds above the 85th actually are getting safer? If the NMA wants scientificly set speed limits why then do they ignore some of the most important science that deals with the kinematics of a crash? There is a curve that shows the relationship between speed and risk of casualty crash but you will never see it on anything sponsored by the NMA because as speeds go up on this graph so too does the risk of being involved in a casualty crash. The NMA cherry picks very specific scientific studies and classifies all the rest as biased so that they can discount the findings that don’t support their desires for triple digit speed limits.

  15. Phil Mckrackin says:

    A quote from one of the numerous scientific tudies that are cited to support the NMAs push to raise all speed limits to the 85th percentile speed. “The data collected durring this study indicate that there are no benefits, either from a safety or operational standpoint of view, from establishing speed limits less than the 85th percentile speed. This does not mean that all speed limits should be raised.”

  16. Phil Mckrackin says:

    Also 1992 Parker (the holy grail of speed limit studies) doesn’t say exactly what the NMA and it’s supporters cite it as saying. It says that for the greatest safety benefit speed limits should be set within 5mph of the 85th. It also has a list of criteria other than the speed distribution that should be considered when setting speed limits. Also the curve drawn above was not taken from any of the numerous studies that are cited as showing us what the NMA is asserting here. One must ask why if the study supports this isn’t the graph from one of those studies? One thing the article above says that I agree with: “The key to improving traffic safety isn’t slowing everyone down, it’s getting drivers to travel near the same speed.” This is true and it is true at any speed not just the triple digit speed limits that the NMA is working towards. They go on to say “This is something that the 85th percentile accomplishes naturally.” which is somewhat true. Something that the NMA doesn’t mention here is the 10mph pace speed which is the 10mph speed bracket that holds the largest concentration of traffic. The 85th is above that and depending upon the speed distribution depends on how far above. Ironically this is one of the additional criteria listed in Parker(1992) that should be considered in addition to the 85th percentile speed. The NMA however would have you believe this is a useless criteria and all that needs to be considered is the 85th percentile speed. Why? because they want higher speed limits at any cost.))

  17. Phil Mckrackin says:

    The NMA is very quick to accuse politicians of being greedy, police of being corrupt and citizens of being ignorant for wanting low speed limits. The NMA acusses that most speed limits are under posted to create a revenue colecting cash cow through speed traps, speed cameras and enforcement for revenue programs.
    Ironically the NMA never explains how you as a driver can combat speed traps, speed cameras and revenue collecting enforcement of speed zones. Now this is really simple lets see if you idiots can grasp the concept. All you need to do to avoid being targeted for enforcement is OBEY the speed limit as it is set on the signs or in the statutes(COMPLY WITH THE LAW). Viola, you cut the aledged corrupt system off at the knees. No money from speeding citations and the system goes bankrupt except that there are other traffic violations that result in fines and the money goes exactly where the speed limit fines go but those violations aren’t for revenue, only the speeding ticket fine money is used for revenue. I have spoke to some really intelligent guys on here and some really dumb guys. I know why the dumb guys don’t get it but what I can’t figure out is why the smart guys believe all the propaganda that the NMA throws at them?

  18. George 2 says:

    Sick of this country under posted speed limits. Speed traps, speed cameras, and traffic light cameras everywhere. No freedom or enjoyment of the road driving in America. Why we allow cops to harass citizens everyday is intolerable. If i hit the lottery i would move to a state that has a minimum of 75 highway speed limits or move to Europe. Been to Europe 4 times and what a pleasure not feeling oppressed and worried while driving.

    • Randy says:

      I will be one to help donate to your fund of moving to Europe. If you feel oppressed you must live in the wrong place. I do not feel oppressed by any police. I forgot you are paranoid.

      By the way if you drive like you are supposed to you should have no worry about being oppressed. Do not drink and drive and stop when the light is red and follow all the other things you should have learned in drivers training then you should have nothing to worry about.
      If the speed limit is too low for you to make it through life then stay home. If you have a need to drive 25 miles in 9 minutes to make it through life you need to get another life. I have seen dozens of people break the law for a few seconds of time savings. Are you that kind of idiot?

    • Phil Mckrackin says:

      Randy count me in on helping! Remember when all the celebrities started saying “if Bush gets re-elected I’m moving out of this country!” After Bush got elected none of them moved. Probably because you and I randy were not there to offer our help in support of them leaving.

  19. James says:

    Why yes Randy, yes I would. I have never seen a single person try to drive 75mph in every traffic condition, on every road.

    • Randy says:

      James my point being is that many poor drivers who think they are the opposite try to drive the same speed no matter what. Coming home tonight is an example. It was raining out and I was on a two lane country type road with a 55 mph speed limit most of the way. It is a curvy hilly road with tall corn on the side of it. Most everyone was traveling the speed limit which is 55 because it was raining and it is not the Autobahn. There was a guy passing other vehicles where ever possible. On the 10 to 12 mile road he probably beat me by far less than a minute because I even caught up with him once because he was slowed by other vehicles. If everyone else was traveling a safe speed that got everyone home in a quick amount of time why would an idiot be tailgating and passing on rainy roads? Not because he needed to but because he was stupid. I am sure he had nothing at home to do that needed that extra few seconds of his time.

    • Phil Mckrackin says:

      Randy why argue with him? He drank the Kool-aid. I believe he is a member of the original organization whose mission statement was “higher speed limits at any cost.” There is no reasoning with this person or showing him that there is just as much scientific evidence that raising speed limits creates risk to drivers. Did you ever notice these guys always use the risk curve of simple crash. They never will show you the curve associated with risk of casualty crash because it is mostly a function of speed and as travel speed increase so too does the risk that you’ll be injured or killed in a crash.

  20. Mikw Roberts says:

    What isn’t covered is when the speed survey happens. At rush-hour the road I take to work averages 50mph… after 10pm, it’s 75, both safe and comfortable speeds for the conditions, but our laws make no distinction.

    • Jeff T says:

      Here in CA, speed surveys are required to last 24 hours, and the public is NOT to know it’s happening. If people saw measuring equipment, some would slow to a crawl, while others would speed up. Either would skew the results.

    • Randy says:

      The only problem is that many try to drive the 75 mph no matter what the conditions. Would you disagree with that?

      That is also a good idea to have faster speeds when the drunks are out to get them off the road quicker.

  21. Hubcap says:

    “Use of the 85th percentile speed acknowledges that 15% of the drivers are traveling above a speed that is reasonable and proper. This is the 15% of motorists at which enforcement action is directed. Studies have shown that this is the group of motorists that cause many of the crashes and have the worst driving records.”

    OK, that makes perfect sense.

    But the graph suggests that someone driving 15 mph under the 85th percentile speed is substantually more likely to cause a crash than someone going 15 mph faster. Seems like more enforcement directed at the slower drivers would be the most effective way to reduce accidents.

    • Randy says:

      Hubcap there are a few things that are not shown in the statiistics. Many of these graphs do not tell you that the reason many of the crashes occur when someone is traveling slower is because they are slowing to make a stop or a turn off or many other things and with tailgaters within a second behind them they will get hit.

      Does this site promote trying to slow down the fastest 15% ? Heck no. Completely the opposite.

      I have also saw that the fast group passes people in a no passing zone within a mile or two of their destination and are much more likely to tailgate. Hubcap there are idiot drivers out there.

    • Hubcap says:

      Randy,
      For once you’re almost right. The graph doesn’t show anything about what causes the accidents. And you are also correct that NMA is not focused on slowing down the upper 15%. NMA’s concern is bringing the SPEED LIMIT within the 85th percentile rule because that is where the fewest accidents occur.

      The rest of it you are fabricating from thin air. But I agree that there are some idiot drivers out there; I have done saw them with my own eyes too!

    • Phil Mckrackin says:

      What hubcap isn’t getting here is that the risk of simple crash is not the same as risk of casualty crash. We measure safety by how many casualty crashes occur but then the NMA believes we should set the speed limits soley by the simple risk of crash curve without ever considering severity of crash. As Hubcap has pointed out the risk of simple crash at 15mph under the 85th to be much greater than the risk above the 85th. Simply put this risk curve does not account for the differences in crashes. Although the risk of crash is higher below the 85th the risk of casualty crash is much lower because the risk of casualty crash is a function of speed. Also Hubcap, just to let you know the NMA doesn’t support the 15% above the 85th being enforced against they feel that there should be a mandatory grace above and beyond the 85th percentile to allow for all the drivers at or below the 95th percentile to be free from enforcement. Do the math! If the best place for safety reasons to set the speed limit is at the 85th percentile why would we allow 2/3 of those who are defined as unlawful go without retribution? Wake -up people you are the pawns in a political struggle and the NMA will say anything to get your support.

    • PMckrackin says:

      Also the area under the 85th percentile contains 85% of the traffic stream while the portion of the curve above the 85th contains only 15%. That the risk of crash below the 85th looks as if it has an equal cahnce of crash as those above the 85th, that isn't absolutely true. To illustrate what I mean let's say the traffic stream is 100 cars 85% or 85 cars are at or under the 85th percentile and 15% or 15 cars are traveling faster than the 85th. Say the risk is 5 cars will crash at a point that looks the same because of the number of incidences…….

    • PMckrackin says:

      5 cars of the 85 that ar at or below the 85th percentile is 1/2 of 1% of that group. While the number of incidences loos the same the 5 vehilse above the 85th makes up 33% of that group. would you say you are safer having the risk of being 1 of 5 vehicles that makes up 1/2% of the group you are traveling in or 1 of 5 that makes up 30% of the group you are traveling in? the chance that you'll be 1 of those 5 below the 85th is 1.17%, while your chance of being 1 of those 5 above the 85th is 6.66%.

    • PMckrackin says:

      If using the 85th percentile speed acknowledges that 15% of the drivers are traveling ABOVE a "REASONABLE and PROPER" speed why is it that members of the NMA and the NMA itself want the speed limits posted at the 85th and then not enforced until the 95th percentile speed?

  22. Randy says:

    This article just proves that Texas and Michigan are full of liars, or that I have absolutely zero reading comprehension.

  23. Randy says:

    The same lies as usual. Speed limits do nothing they say. What if the speed limit was 65 mph and and you get a reckless driving on your record if you drive 15 mph over the limit. What would many do if the speed limit was dropped to 60 mph? Guess what many of the faster drivers would do? I will give you one guess. Another thing is every report that I have ever read said that the closer in speed vehicles are traveling the less the accident rate. If you raise the limit to the fastest 15 percent of the drivers might that be possible to have a speed far faster than the lower 50% causing increased accidents.

    • Jim says:

      Randy – no one cares what you have to say.

    • Randy says:

      Jim,

      You are totally right. Only I, the “no one”, i.e., nobody, care about what I have to say.

    • Hubcap says:

      Randy,

      Were the other 35% of drivers in your senario abducted by aliens? Raptured? Eaten by zombies? Hiking the Appalachian Trail?

      Where did they go?!

    • George [C] says:

      What if you built a high quality, high speed limited access, multi-lane highway and people had lane discipline?
      http://www.youtube.com/watch?v=IDnp3tsTzpM

      damn, those zombies even use turn signals. even while passing somebody people at 50-75mph

      and then another zombie challenged one to ‘nut up or shut up’ (a 100mph lane differential qualifies)
      http://www.youtube.com/watch?v=O89UWHnFUl0

      What Randy doesn’t want to articulate is that his position in the ‘argument’ is that good drivers should be brought down, not inferior drivers improve.
      Don’t raise up the bottom, drag down the top. That won’t find any converts here.

    • PMckrackin says:

      So your position is that we should all improve our driving so that Mario Andretti can drive as fast as his ability allows and we would be compatible. There is a reason he was susch a great racer, his ability was not easily matched. There needs to be a range of ability that extends from wanna be race car drivers, like yourself george and my grandmother because that is who uses the roadway. Since it would be impossible to teach my grandmother how to compete with Mario Andretti or even you george, maybe the Mario andrettis of the world need to realize they are not the only roadway users.

    • Randy says:

      George what you and other idiots do not get is that often some of the poorest drivers are the fast ones. It does not take any intelligence to increase your foot pressure on the accelerator. Many of them show it too.

    • Randy says:

      George no wonder they are placing speed limits on those roads in Germany now. With people just out to see what they can do you will find all kinds of idiots. One thing I did notice from those videos is that the quality of the roads is better than I have ever seen in the US. Almost no vibration at higher speeds. No bumps at all. I also noticed that no where in the US have I ever seen that few of cars on a 3 or 4 lane highway. There was less than 1 car per lane mile. It wouild cost us 100s of Trillions of dollars to set up a highway system like that all over the US.

      If they tried to drive that fast in the US traffic they would be dead. Another thing I left off George is that it did not take a great driver to do what he did. Point the car straight and step on the gas and you say we are keeping great drivers down.

    • George [C] says:

      You are going to do a top speed run in your M6 during peak utilization hours, of course!
      Did you bother to investigate as to when he went out, early Sunday morning.

      Not all of the Defense interstate road system needs to be three or more lanes.

      The entire infrastructure has been intentionally neglected, so before the high speed maglev trains arrive, how about throwing 5 trillion to redo the roads/bridges, correctly.

      Speed limits are coming because of the non-German road users.

      In the 850csi it takes a precise hand on the steering, and a delicate foot on the throttle. The throttle isn’t a binary switch.

    • Randy says:

      George if you pay for all of our highway improvements we will get you an exemption to drive as fast as you like.

      As far as the delicate driving the driver was doing that is bull. It was mostly all straight driving and mostly fulll speed driving. Big deal if you see something a mile ahead of you then you slow down. You are an idilot George.




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