[Occasion and risk for detecting driving in alcoholic intoxication]

Detection of offenders driving while intoxicated (DW) (mandatory BAC limit at 0.50%) in Finland was investigated. Almost every fifth offender was detected at road blocks and every tenth of them because of abnormal driving. Compared to the local police the national traffic police had arrested much more offenders for traffic violation (38% vs. 11%) but much less because of accidents (12% vs. 23%). The reason of detection was in a significant way dependent on the following variables: BAC, stage of inebriation, vehicle, day of week and hour of day. The risk of detection is very low, i.e. about 1 to 300. However, the risk has doubled from 1979 to 1984, but thereafter slightly declined. The study provides information for the strategy of the police in traffic supervision.