NHTSA Releases Two New Studies on Impaired Driving on U.S. Roads

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Results from the 2013-2014 National Roadside Survey of Alcohol and Drug Use by Drivers, indicate a steady decline in the prevalence of alcohol use by drivers. But, as drinking and driving continues to fall, use of illegal drugs or medicines is rising.

The survey, conducted by the National Highway Traffic Safety Administration (NHTSA), found the number of drivers with alcohol in their system has declined by nearly 30% since 2007. Conversely, the number of drivers with marijuana in their systems has grown by nearly 50% since 2007. Overall, 22% of drivers tested positive for some kind of drug, including illegal drugs, prescription or over-the-counter medications.

According to NHTSA Administrator Mark Rosekind, tougher laws, crackdowns and campaigns against drunk driving have helped to reduce the number of cases by more than 80% since the agency began conducting these surveys in 1973. “At the same time, the latest Roadside Survey raises significant questions about drug use and highway safety,” he says.

To better understand of the correlation between drug use and crash risk, a second survey, compared data collected over a 20-month period from more than 3,000 drivers who were involved in crashes, as well as 6,000 drivers who did not crash. The study found that marijuana users are more likely to be involved in crashes, but notes that this may be due in part to the fact that many marijuana users are already part of groups at higher risk for crashes (i.e., young men).

“These findings highlight the importance of research to better understand how marijuana use affects drivers so states and communities can craft the best safety policies,” says Jeff Michael, NHTSA’s associate administrator for research and program development.

To further understand the risk of drugged driving, the agency plans to conduct a series of additional studies including the Washington State Roadside Survey, which will assess risk in a state where marijuana has been legalized. Click here to learn more.