Speed Limits Really are for Everyone

Speeding car

Nearly every adult in this country drives a car on a regular basis.  Yes, many people commute via public transportation, ride a bike, or walk to work; but even many of those people drive a car at least occasionally.

According to 2015 data, Americans drove over 3.2 trillion miles and there were over 218 million licensed drivers.  Traffic is increasing, everyone is in a hurry, and distractions abound.  All of this adds up to a pretty serious safety concern for everyone.  That is unless you don’t think that 40,000 fatalities and over 2,000,000 injuries annually is a concern.

The comedian George Carlin once said, “Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?”  This observation is worth a chuckle, but when we really consider what this means it definitely points out another area of concern.  We all think we are better drivers than the people around us.  This was alluded to in a previous Safety Net post entitled, “Death by Text…or Other Distraction.”  So let’s take a look at the most common cause of traffic accidents, why we have the traffic laws we have, and what you can do to be a safer driver.

According to the National Safety Council, “Speed Kills:  Always Has, Always Will.  Speed limits are in place for a reason, yet almost everyone exceeds the posted limits regularly.  Maybe if we better understand why the limits are set we would be more likely to adhere to them.  After all, speed is often cited as the leading cause of traffic collisions.  Remember, speed limits are not arbitrary.  “Maximum speed limits are laws; therefore, speed limits are set for the protection of the public and the regulation of unreasonable behavior on the part of individuals”.1 

Speed limits are set by several methods with public safety at the core of each.  Many factors are considered including the prevailing traffic speeds.  Limits are often set, at least initially, at the 85th percentile speed- the speed at which 85 percent of free-flowing traffic is traveling at or below.  Adjustments are then made based upon infrastructure and traffic conditions.  But changing the speed limit, even 5MPH, can have significant impact on safety.

In 2014 the speed limit was raised on a 24 mile long stretch of Interstate 295 between Portland and Brunswick, ME.  The limit was changed from 65MPH to 70MPH.  In the following three years, vehicle collisions increased 66 percent.  As a result, the speed limit was returned to 65MPH in March 2017.  The preliminary results indicate a drop in collisions since.  Keep in mind, this was only a 5MPH change! 

When a driver exceeds the posted limit, or drives too fast for prevailing conditions, he/she is rolling the dice and assuming that snake eyes won’t show up.  Most of the time luck prevails and nothing bad happens.  This is the classic “positive consequence” that will trigger the behavior to occur again.  We all know there are many possible “negative consequences” for this behavior: a ticket, collision, injuries, poorer fuel mileage, and wear and tear on the car to name a few.  But clearly these negative consequences are not powerful enough to modify behavior.  This is because these negative outcomes are rare, they are uncertain so don’t serve to change our behavior. 

The irony is that for most commutes, driving faster doesn’t actually result in arriving at the destination much sooner.  The difference between driving 65MPH and 70MPH on a 10-mile trip is only about 45 seconds, and this assumes constant speed.  Add in traffic congestion, school buses, construction, traffic lights, and merging traffic and you’ll never save even 45 seconds! 

What’s the right answer?  Follow the traffic rules, observe the posted speed limits, and leave enough following distance between your vehicle and the one in front of you.  You’ll get to your destination about the same time, you’ll save gas, you’ll be in a better mood when you arrive, and you’ll reduce the odds of being involved in a collision.  There really isn’t a down side. 


1  Methods and Practices for Setting Speed Limits: An Informational Report, Federal Highway Administration, FHWA-SA-12-004, page 1.

By Randy Klatt