Speed limits are designed to denote the fastest speed deemed safe to maintain driving in favorable weather conditions. Researchers at the DOT (Department of Transportation) have long sought to see what, if any, changes are seen in driver speed and behavior with increases or decreases to speed limit. Here, we break give you the basics of their research findings.
DOT studies have shown that changing the posted speed limit tends to have minimal effect on the average speed of motorists. Changes of between 5-20 MPH had little to no effect on speed. The slowest drivers actually increased their average speed, whereas there was no change in the speed of the fastest drivers.
Interestingly, at experimental sites where the speed limit was lowered, there was an average increase in accidents of 5.4%, whereas at experimental sites where the sped limit was raised, accidents decreased by 6.7%. What this shows us is that speed limit is more effected by the speed maintained by other drivers, and what the driver themselves feel comfortable with.
