The main purpose of the study is to determine the accident risk when driving under the influence of psychoactive substances, including alcohol (DUI). Other aims are to find out the prevalence of psychoactive substances in road traffic and to obtain information on the role of these substances in road traffic accident causations.

For the purposes of the study, drivers of motorised vehicles are randomly stopped and interviewed and breath alcohol is recorded. Also, an oral fluid sample is taken and psychoactive substances are investigated in the laboratory. For cases, drivers injured in traffic accidents are asked to participate to the study. A whole blood sample and, if possible, an oral fluid sample is taken and psychoactive substances are determined in the laboratory. Also, people diseased in road traffic accident are included in the study. The information required for these subjects are taken from a register database.

The study is part of an EU-project DRUID. Altogether 13 European countries take part to the study.

Inclusion Criteria:

• 18 years or older
• driver of a motorised vehicle or bicycle
• is willing to participate to the study (not applicable to the diseased drivers; information obtained from a register database)

Exclusion Criteria:

• 17 or younger
• not the driver of a motorised vehicle or bicycle
• does not want to participate (not applicable to the diseased drivers; information obtained from a register database)

drivers of motorised vehicles and bicycles in general road traffic or drivers of motorised vehicles and bicycles, injured or killed in road traffic accidents