In 1998, a field study funded by the Federal Highway Research Institute (BAST) of Germany was conducted with drivers at discotheques. Subjects were contacted by researchers from the Centre of Traffic Sciences, Würzburg (IZVW) and asked to participate in a short interview concerning drugs and driving. Subjects who had consumed drugs and had either been driving, were going to drive or indicated that they had been driving under the influence of drugs at other occasions were asked for an extended interview, a driving-simulator test and for blood, urine and saliva samples (N = 241). Additionally, sober control subjects (N = 59) and subjects under the influence of alcohol (N = 45) were included. The study examines the effect of cannabis (two groups: acute and previous consumption) and amphetamines and ecstasy (two groups: low and high concentration) alone and in combination with alcohol on driving performance. Driving performance was analysed by means of a driving-simulator which evaluates the ability to maintain lateral position and speed, tests peripheral and central attention and risk-taking behaviour. The analyses show that consumption of cannabis and amphetamines/ecstasy, only, does not adversely affect driving behaviour. However, the combination of the two substances with one another and or alcohol leads to a substantial impairment of driving and performance in secondary tasks.
Samenvatting