- Researchers have found that most motorists exceed posted speed limits. Motorists exceed speed limits for several reasons: (1) they believe speeding carries little risk; (2) they usually drive at what they perceive is an appropriate speed, regardless of the speed limit; and (3) advisory speeds have little if any effect on motorist speeds, especially when a motorist is familiar with a road.
- Even after speed limits are increased, motorists will violate the new posted speeds, expecting law enforcement will tolerate the driving 5 – 10 mph over the speed limit.
- On most urban or rural highways, increasing or decreasing posted speed limits produces a 1 – 2 mph change in the 85th percentile speed in the same direction as the change.
- On interstates, increasing posted speed limits increases the 85th percentile speed by 1 – 3 mph as well as speed dispersion.
CONTACT:
Chris VanDyke
Research Scientist | Program Manager
chrisvandyke@uky.edu
