Drugs and driving in Vienna, Austria

Drugs that affect the central nervous system are generally assumed to have the potential to impair driving ability. In a retrospective survey, police files and the results of toxicological urine analysis from drivers suspected of driving under the influence of drugs in Vienna from 1993 to 1996 were investigated. Decisive for police intervention was "unsafe driving" (swerving, hesitating, going too slowly, etc.), driving at high speed within the city limits, driving through red lights or stop signs, and driving at night without lights. In one-fifth of the cases drivers caused a traffic accident. Casting suspicion on driving under influence of drugs was mainly caused by impaired coordination of movements, bloodshot eyes, slurred speech, drowsiness, conspicuous behavior, and changed pupils. In the majority of the study population more than two symptoms were recorded by police. In 94% of the cases police suspicions could be confirmed by toxicological urine analysis.