Samenvatting
Both simulator and on road studies have shown marihuana impairs driving performance. Major effects of marihuana driving performance. Major effects of marihuana are to reduce speed, to reduce risk taking behaviour, and to reduce ability to perform monitoring tasks while driving. The study described here examines the effects of marihuana alone and in combination with alcohol under conditions of normal social use, i. e. after extended use over an evening followed by night time driving and morning after effects.