Because marijuana impairs judgment and motor coordination and slows reaction time, an intoxicated person has an increased chance of being involved in and being responsible for an accident.18, 19 According to the National Highway Traffic Safety Administration, drugs other than alcohol (e.g., marijuana and cocaine) are involved in about 18 percent of motor vehicle driver deaths. A recent survey found that 6.8 percent of drivers, mostly under age 35, who were involved in accidents tested positive for THC; alcohol levels above the legal limit were found in 21 percent of such drivers.
18O’Malley, P.M.; and Johnston, L.D. Drugs and driving by American high school seniors, 2001-2006. J Stud Alcohol Drugs 68(6): 834-842, 2007.
19Richer, I.; and Bergeron, J. Driving under the influence of cannabis: Links with dangerous driving, psychological predictors, and accident involvement. Accid Anal Prev 41(2): 299-307, 2009.