Cannabis-Impaired Driving: A Public Health and Safety Concern

Cannabis, the most common illicit drug identified in motor vehicle crashes, had a higher prevalence than alco-hol in drivers ’ blood or oral fluid specimens in the US in the 2013–2014National Roadside Study (1). In fact, the percentage of weekend nighttime drivers with measure-able 9-tetrahydrocannabinol (THC)2 in blood or oral fluid increased to 12.6%, a 48 % increase since 2007 (2). Cannabis use is increasing since the legalization of can-nabis in 4 US states and the approval of medical cannabis in 23 US states and many countries. The incidence of THC-impaired driving increased in Washington state from 19.1 % before to 24.9 % after cannabis legalization (3). These statistics highlight an important public health and safety concern: cannabis-impaired driving. In this issue of Clinical Chemistry, for the first time