Driving and the combined use of drugs and alcohol in The Netherlands.

The extent and nature of the use of medicinal drugs by drivers who had undergone a blood test on suspicion of driving under the influence of alcohol was ascertained by analysing some 40,000 case records in which the suspect had been questioned about the use of drugs. No chemical analyses were performed. 9.7% of the road users indicated that they used drugs in combination with alcohol, and more than 50% of the drugs used must be considered to have a negative impact on driving performance. The influence of the combined use of benzodiazepines and alcohol on behaviour was also investigated. The finding here was that drivers using these drugs should be warned against the consumption of alcohol.