motor vehicles

What the research shows about marijuana and driving

"Several meta-analyses of multiple studies found that the risk of being involved in a crash significantly increased after marijuana use13 -- in a few cases, the risk doubled or more than doubled.14-16 However, a large case-control study conducted by the National Highway Traffic Safety Administration found no significant increased crash risk attributable to cannabis after controlling for drivers’ age, gender, race, and presence of alcohol.17"