Safe Transportation Research & Education Center

Driving can be impaired by a variety of legal and illegal drugs, substances, and medications. These various substances can impair cognition, attention, coordination, and other brain functions critical to driving safety. Unlike alcohol, the mechanism for absorption, distribution, and elimination of drugs from the body, as well as cognitive and behavioral effects differ greatly.

Analyses from SWITRS presented in this program area refer to drug-involvement and include fatal and serious injuries where law enforcement reported the driver to be under the influence of drugs. Crashes in the program area are defined as where one or more drivers tested positive for a drug that could cause impairment or was reported as driving under the influence of drugs, depending on which data set is used.