Gravity is constant at 32 ft/sec2. The speed of light remains the same at 186,282.4 mi/sec. The sound barrier is 770 miles per hour in the air and the Mississippi River travels at a speed it determines. Traffic is no different. You and I travel at speeds we determine “reasonable and prudent” regardless of the posted speed limit. The nation’s first speed law came from Hartford, CT in 1901 saying, “No one should drive at a speed greater than is reasonable and prudent under existing conditions.”

Governments big and small, don’t read the research and post speed limits they consider “safe” and then wonder why nobody is obeying their speed limits. We have tried this before. During World War II, a National War Time Speed Limit of 35 mph was imposed. In 1973, the Arab Oil Embargo saw a national 55 mph speed limit. Nobody obeyed it. Now, with dramatic increases in fuel prices and our dependency on foreign oil, calls have been made to again return to a national speed limit of 55 mph. It didn’t work before, and it won’t work now.

We expect governments to make intelligent decisions based on proven research. It appears they are blind and don’t read what they have paid to be investigated. Before you or I make medical decision, we research the surgery and the doctor performing the operation. Before we buy a new car, we research its reliability, economy, and safety. Before we send our kids to college, we research the institution’s reputation for educational excellence. We do our research before a decision, not after. I have attended numerous city council and school board meetings considering reducing speed limits.... “We will slow them down with a lower speed limit!” They don’t and won’t slow down. It’s the Mississippi River syndrome. Let’s look at the research on speed limits and compliance.

Washington State Department of Transportation, http://www.wsdot.wa.gov/biz/trafficoperations/traffic/limits.htm, states, “But if you lower the speed limits, people drive slower, Right? The answer is no, just as people don’t automatically drive faster when the speed limit is raised. Studies have consistently demonstrated that there are no significant changes in the 85th percentile speed following the posting of a revised speed limit.”

Effects of Raising and Lowering Speed Limits, U.S. Department of Transportation, Federal Highway Administration, Report No. FHWA-RD-92-084, Martin J. Parker, http://www.ibiblio.org/rdu/sl-irrel.html, conducted in 22 states at 100 locations covering some 1.6 million vehicles. This study found “posting lower speed limits does not decrease motorist’s speeds. Increasing the posted speed limit did not create a corresponding increase in speed. Lowering speed limits more than 5 mph below the 85th percentile speed of traffic did not reduce accidents and raising speed limits in the region of the 85th percentile speed has an extremely beneficial effect on drivers complying with the posted speed limits.”

Ohio Department of Transportation, http://www.dot.state.oh.us/dist3/planning/TRAFFIC/Speed.asp relates, “Before and After studies consistently demonstrate that there are no significant changes in traffic speeds following the posting of new or revised speed limits. Furthermore, no published research findings have established any direct relationship between posted speed limits and accident frequency.” The report goes on to say under Common Misconceptions: “A lower speed limit slows people down.” It doesn’t! “A high speed limit makes people speed up.” It doesn’t!

National Safety Council, Traffic Safety Magazine, November/December 1997 published Speed Measurement Laboratories Inc. research “Reasonable And Prudent Speeds.” This research looked at average speeds on rural interstates in 1987 when states were allowed to set interstate speeds of 65 mph and compared the same mile marker speeds on the same interstates in 1996 when the federal government allowed states to increase their speed limits above 65 mph. The study compared some 24,014 vehicles over a ten year period. Comparing the speeds of Montana with no speed limit to Colorado at 75 mph, South Dakota at 75 mph, and Texas at 70 mph the research confirmed Martin J. Parker’s findings. There was no significant difference among the states in average and 85th percentile speeds although Montana did not have an interstate speed limit. SML also found as speed limits increased, speed limit compliance increased. This study was replicated in 2006 in Great Falls, MT by SML.

National Highway Traffic Safety Administration, Traffic Safety Facts, http://nhtsa.gov/statistics. A Field Test of Rational Speed Limits in Gulfport, Mississippi, Number 338, December 2007. This field research studied speed limit compliance before and after posting of 85th percentile speeds. It found when the speed limit was changed from the existing 35 mph to the new 50 mph a dramatic change happened in speed limit compliance. When the speed limit was 35 mph, 38.3% of drivers were exceeding the 35 mph limit by 10 mph. After the speed limit was changed to 50 mph, only 6.9% of drivers were driving 10 mph over the new limit.

Arizona Department of Transportation, Establishing Speed Limits, http://azdot.gov/highways/traffic/Speed.asp. Arizona found what other states have found; “Speed limit signs will not slow the speed of traffic, speed limit signs will not decrease the accident rate and increase safety". Raising the posted speed limit will not cause and increase in the speed of traffic.

Texas Transportation Institute, Texas A & M University, http:tti.tamu.edu/documents/0-4707-S.pdf Summary Report 0-4704-S, “Drivers tend to travel as fast as they feel comfortable, absent of enforcement". Even in areas posted as work zones with reduced speed limits, if there are no indications that active work is taking place, drivers will generally maintain the speed they were traveling before entering the work zone regardless of the posted work zone speed limit.”

Did The 65 MPH Speed Limit Save Lives? Lave and Elias, www.uctc.net/papers/069.pdf, University of California - Irvine, This research looked at 1987 when the federal government allowed states to raise their speed limits to 65 mph. The research states, “We find that the 65 mph speed limit reduced the statewide fatality rate by 3.4%-5.1% compared to states that did not raise their speed limits and maintained 55 mph.

Federal Highway Administration, http://www.ibiblio.org/rdu/sl-irre0.html Driver Speed Behavior on U.S. Streets and Highways, This study was conducted on 52 roads in four states: Delaware, North Carolina, Colorado, and Arizona. This research reported: “speed limits which are set artificially low tend to be ignored.” The assumption was that as you increased the speed limit by up to 15 mph drivers would automatically drive the increased limit. The answer was no. “Raising the speed by various amounts up to 15 mph has little or no effect on speeds over a broad range of road types and speed levels. Conversely, lowering the speed limit will not slow down traffic.”

This is not an opinion! It is based on fact and research. You can’t hold a sign up telling the Mississippi River to slow down. It won’t! Setting the national speed limit at 55 mph won’t work!

speed@speedinglimits.com