This report gives an account of a study into the feasibility of determining the risks of the use of alcohol, drugs, and psychoactive medicines by motorists. This study was carried out by SWOV in the period May 2000 to August 2001, in cooperation with the University of Utrecht, the Tilburg police district, and the St. Elisabeth Hospital in Tilburg. The study preceded the European IMMORTAL (Impaired Motorists, Methods Of Roadside Testing and Assessment for Licensing) research project. This large-scale project started in January 2002. The chosen research method in the feasibility study was that of a so-called case-control study. The use of psychoactive substances by (seriously) injured drivers is compared with the use by a random sample of drivers. The substances involved were: alcohol, opiates (codeine, morphine, and heroin), methadone, benzodiazepines, tricyclic anti-depressants, barbiturates, cannabis, cocaine, amphetamine, and ecstasy. Urine or blood specimens were used to detect these substances. Attention is paid to the size and possible selectivity for substance use, of the non-response in the research and control groups. The conclusion of the study is that the research method used can provide a reliable picture of the relative injury risks associated with the use of alcohol, drugs, and psychoactive medicines. The study determined no significant risk enlargement (yet) for single-use of cannabis, ecstasy and/or amphetamine, cocaine, opiates, tricyclic antidepressants, or a relatively small quantity of alcohol (blood alcohol content (BAC) of 20-50 mg/100 ml). Significant risk enlargements could be established for benzodiazepines, combinations of different drugs, and a BAC more than 50 mg/100 ml. By far the highest relative risk, however, was found in the combined use of (a lot of) alcohol and drugs.
Samenvatting