Prevalence and Risk of Injury in Europe by Driving with Alcohol, Illicit Drugs and Medicines

Prevalence and injury risk of driving with alcohol, illicit drugs and medicines have been estimated as part of the Driving under the Influence of Drugs, Alcohol and Medicines (DRUID) project of FP6. Prevalence of the drugs in the driving population was based on roadside surveys in thirteen European countries, prevalence in seriously injured drivers and killed drivers was based on data from nine countries. Blood and/or saliva samples were collected and analysed for ethanol, amphetamines, cocaine, cannabis, illicit opiates, benzodiazepines, Z-drugs and medicinal opioids. The estimates were based on concentrations at and above equivalent cut-offs in blood and saliva, enabling the inclusion of both blood and saliva in the calculations. Drivers in traffic served as the control sample and seriously injured/killed drivers as the case sample for estimating the risk as calculated by means of odds ratios, adjusted for age and gender. The alcohol prevalence (concentrations = 0.1 g/L) was much higher than the prevalence of other drugs, with highest alcohol prevalence in all three study samples in the southern and western European countries. Combined alcohol/drug use and multiple drug use were far more common in accident-involved drivers than in drivers in traffic. The prevalence of other drugs was highest in the driving population in southern Europe with THC as most common, whereas benzodiazepines dominated in the northern countries of Europe. Based on data from all involved countries, the risk of being seriously injured or killed significantly exceeded 1 for alcohol concentrations = 0.5 g/L and almost all other drugs. Odds ratios differ between age groups and countries, but overall, alcohol concentrations = 1.2 g/L together with combined alcohol/drug use had the highest odds-ratios, followed by alcohol concentrations between 0.8 and 1.2 g/L and multiple drug use.