Psychoactive substance use and other driver-related risk factors of road traffic injury: An epidemiological study of associations, trends, and crash characteristics

Road fatality numbers in Norway are low compared to most other countries, and decreasing. Since 2001, the road safety work has been based on a stated vision of zero lives lost. In order to further adapt the preventive measures, recent risk factors and trends must be investigated in-depth. The aims of this thesis were to investigate relations between impairment from alcohol or drugs and other risk factors of road traffic injury, study crash characteristics, and to reveal trends in use of alcohol, drugs and other common unsafe driving behaviours. Due to a relatively low number of fatal crashes in Norway, drivers arrested by the police on suspicion of drug/drink-driving were included in order to investigate trends in substance use that could predict trends among drivers at high risk of crash involvement. The results are based on information from more than 100,000 drivers arrested by the police and 1,220 drivers killed in road traffic crashes. The prevalence of alcohol declined among all age groups of drivers. Amphetamine increased among the oldest and declined among those