English summary: DRUGS AND DRIVING IN FINLAND BEFORE AND AFTER THE ZERO TOLERANCE LAW

On the 1st of February 2003 the legislation in Finland was changed so that a person driving a motor vehicle with any amount of an illegal drug or its metabolite found in his/her blood can be sentenced without any other signs of impaired driving ability ("zero tolerance law"). While blood alcohol concentration is limited to a maximum of 0.5?, any amount of an illegal drug or a CNS affecting drug found in blood and without a legal prescription is punishable. We explored the effects of the new law on the appearance of drugs and alcohol in the suspected "driving under the influence" (DUI) cases as well as the reasons for capture of the drivers. The drug and alcohol findings in suspected DUI samples sent by police officials to the drug research laboratory of the National Public Health Institute in one-year periods either before (n = 1024) or after (n = 1351) the enforcement of the law were compared. The number of drug analysis requests increased by a third after the enforcement of the zero tolerance law. The most common reason for examinations of drivers was traffic accident, and as many as 95% of the samples were positive for some illegal drug and/or alcohol in both study periods. The most common laboratory finding was alcohol followed by benzodiazepine drugs and amphetamine. Simultaneous use of several substances was common, and approximately half of the drivers in both study periods had taken both alcohol and benzodiazepines. The results suggest that the new law may have lowered the threshold to request analyses for drugs other than alcohol by police in traffic situations.