Use of marijuana and prescription drugs is increasingly prominent among drivers on America’s roads, which raises a new safety challenge. While it’s illegal across the United States to drive while drunk (with blood alcohol concentrations [BACs] of .08 of higher) the laws involving drugged driving vary across the states. NHTSA is working to better understand the challenge of drugged driving to help address the issue and save lives.
Understanding the Challenge
NHTSA is working to broaden its understanding of drug use among drivers so the agency can assess the use of marijuana and other drugs and how it may affect the safety of America’s roads.
One recent study, the latest version of NHTSA’s Roadside Survey of Alcohol and Drug Use by Drivers, found a large increase in the number of drivers using marijuana or other illegal drugs. In this 2014 survey, nearly one in four drivers tested positive for at least one drug that could affect safety.
A second survey, the largest of its kind ever conducted, assessed whether marijuana use by drivers is associated with greater risk of crashes. The survey found that marijuana users are more likely to be involved in accidents, but that the increased risk may be due in part because marijuana users are more likely to be in groups at higher risk of crashes. In particular, marijuana users are more likely to be young men – a group already at high risk.
The message of these two surveys is that NHTSA still has much to learn about how illegal drugs and prescription medicines affect highway safety. The agency is working urgently to develop this knowledge because more and more drivers have these drugs in their systems.