English abstract: In the present project information is gathered about two subjects: on the one hand characteristics of journeys undertaken under the influence of drugs and on the other how far consumption of drugs influences the aspects of the performance of the driver which are of relevance to driving capability. In the summer and autumn of 1998 2555 drivers were briefly interviewed in selected events in Bavaria. In accordance with the information given regarding consumption of drugs, in a second step 503 persons were selected who then took part in an intensive investigation. In this investigation, performance capability was checked with the help of a driving simulator and the participants were interviewed in detail. Blood, urine and saliva samples were taken in the course of an additional examination. The investigations revealed that in the case of the sample under investigation, journeys under the influence of illegal drugs occur at least as frequently as journeys under the influence of 0.5 milligrams of alcohol per 1,000 and that in a large proportion of cases involving illegal drugs, the influence of alcohol was also present. Besides this mixed consumption together with alcohol, a combination of various drugs can very often be found. The different psychoactive substances are associated with different age groups and different sexes and also with different driving behaviour. It is particularly significant here that persons generally do not drive if they have consumed alcohol, whereas consumption of illegal drugs has no effect on the decision as to whether to drive or not. In order to judge whether consumption of drugs has a negative influence on aspects of performance which are relevant for driving, a difference was made in accordance with the patterns of consumption which were found between sober control persons, persons under the influence of alcohol, acute and post-acute effects of cannabis and consumption of amphetamines/Ecstasy in low and high concentrations. When only one substance is consumed, clear risk can only be demonstrated for amphetamines/Ecstasy in high concentrations and for alcohol. Acute consumption of cannabis alone does not change driving behaviour, nor does consumption of amphetamines/Ecstasy in low concentrations. Particular risk results from the combination of a drug with alcohol and from the combination of two drugs together with alcohol. However, precisely these combinations can very often be found with regard to the drivers who are under investigation. In the detailed interviews it was shown first of all that it is necessary to differentiate between different groups of drug consumers who exhibit different patterns of consumption and different characteristics. So-called hard and strong drug consumers also drive under the influence of drugs. Those driving under the influence of drugs are also characterised by an increased willingness to take risks and they also drive more often under the influence of a large amount of alcohol. When comparing the conditions relating to driving under the influence of drugs and those relating to driving under the influence of alcohol, it can be seen that willingness to drive under the influence of alcohol depends on the amount which has been consumed and the attitude of the driver. Sanctions applied to driving while under the influence of drugs only influence the drivers as long as they have only limited experience of drug consumption. When the threshold barring consumption has once been crossed, the subjective impression of only a slight decrease in performance undermines the intended effects of the law. However, repressive measures on the part of the state have a clear influence on the judgement of drug driving. Drug drivers who have been once discovered in a police check think that drug driving is a worse offence than drug drivers who remained undiscovered. The results of the present study allow the conclusion that there is still a considerable potential for prevention of journeys undertaken under the influence of drugs. Starting points for various prevention strategies will be drawn from the results of the study. (Author/publisher)
Samenvatting