Introduction
Driving under the influence of alcohol and drugs is a global problem. In Denmark as well as in other countries there is an increasing focus on impaired driving. Little is known about the occurrence of psychoactive drugs in the general traffic. Therefore the European commission initiated the DRUID project. This roadside study is the Danish part of the EU-project DRUID (Driving under the Influence of Drugs, Alcohol, and Medicines) and included three representative regions in Denmark.

Methods
Oral fluid samples (n = 3002) were collected randomly from drivers using a sampling scheme stratified by time, season, and road type. The oral fluid samples were screened for 29 illegal and legal psychoactive substances and metabolites as well as ethanol.

Results
Fourteen (0.5%) drivers were positive for ethanol (alone or in combination with drugs) at concentrations above 0.53 g/l, which is the Danish legal limit. The percentage of drivers positive for medicinal drugs above the Danish legal concentration limit was 0.4%; while, 0.3% of the drivers tested positive for one or more illicit drug at concentrations exceeding the Danish legal limit. Tetrahydrocannabinol, cocaine, and amphetamine were the most frequent illicit drugs detected above the limit of quantitation (LOQ); while, codeine, tramadol, zopiclone, and benzodiazepines were the most frequent legal drugs. Middle aged men (median age 47.5 years) dominated the drunk driving group, while the drivers positive for illegal drugs consisted mainly of young men (median age 26 years). Middle aged women (median age 44.5 years) often tested positive for benzodiazepines at concentrations exceeding the legal limits. Interestingly, 0.6% of drivers tested positive for tramadol, at concentrations above the DRUID cut off; although, tramadol is not included in the Danish list of narcotic drugs.

Conclusion
The present study gives valuable data on drugged and drunk driving. Driving under the influence constitutes a major risk in traffic and the relative high frequency of young men driving while taking drugs is worrying.

Reference
K.W. Simonsen, A. Steentoft, T. Hels, I. M. Bernhoft, B.S. Rasmussen, K. Linnet. Presence of psychoactive substances in oral fluid from randomly selected drivers in Denmark. Submitted