Abstract
The National Institute of Forensic Toxicology in Oslo received blood samples from all Norwegian drivers suspected of driving under the influence of alcohol or drugs until 1996. This procedure was superseded from 1996 in some districts by the use of the evidential breath alcohol analyser, Intoxilyzer 5000N. As this does not detect the presence of drugs in the sample it is possible that the actual cause of impaired driving could be missed. The study described investigated the effect of the introduction of evidential breath alcohol testing on the search for drugs as the cause of impaired driving. This was done by comparing police districts with or without Intoxilyzer with respect to requests for analyses of blood samples from drugged drivers.