This paper summarizes current knowledge regarding the effects of cannabis use on driving. Psychopharmacological evidence has shown that cannabis, unlike alcohol, can be detected several days after consumption. Prevalence data has revealed that cannabis use is increasing, and that as many as 90% of study participants were willing to drive after consuming a typical dose. A review of laboratory studies found that cannabis and alcohol affect different driving tasks. When cannabis and alcohol use were evaluated in simulated and on-road driving situations, drivers were more aware of being intoxicated after using cannabis and thus invoked greater compensatory effort to offset impairment in the driving task. The effect of cannabis use on crash risk has shown that recent use increases crash risk, but not as much as alcohol consumption. This paper concludes that further research is needed before specific transportation policy can be developed for cannabis. (Author/publisher)
Abstract