Road User Behavior

The use of cannabis, prescription drugs, and other drugs are increasingly prominent on roadways in the United States, where 25.3 percent of the nation’s 38,824 fatalities in 2020 were related to drug-involved driving. Driving can be impaired by a variety of legal and illegal drugs, substances, and medications. The effect of specific drugs on behavior and driving skills vary considerably depending on how they act in the brain and are metabolized. They can slow reaction time, decrease coordination, increase aggressive and reckless driving, impair cognitive function, or cause drowsiness. All of...

A speeding-related crash is defined as one where a driver is speeding, racing, driving too fast for the conditions, or driving in excess of the posted speed limit. In the United States, in 2020, over one in four (29.0 percent) fatalities involved speeding, a rate that increased after plateauing in the late 2010s, following a decline earlier in the decade. Speeding reduces a driver’s ability to steer safely around curves or objects, reduces the amount of time a driver has to react to a dangerous situation, and extends safe stopping distances. Analyses presented in the police traffic services...