As part of a major undertaking to establish the role of drugs in highway collisions, the Societe de l'assurance automobile du Quebec (SAAQ) conducted a roadside survey from August 9 to August 29, 1999 in order to determine drug use among Quebec drivers. Regardless of time of day, a BAC above the legal limit (.08) was found in 0.8% of the breath samples. When using the same time period (9 PM to 3 AM, Wednesday to Sunday) as in previous alcohol roadside surveys, BAC>.08 was found in 1.8% (+/- 0.5%) of breath samples in 1999 (n = 2724) which compares to 3.2% in 1991, 3.6% in 1986 and 5.9% in 1981. According to the toxicological analysis of the 2281 urine samples, drugs were found in the following proportions: cannabis (5.22%), benzodiazepines (3.66%), cocaine (1.09%), opiates (1.08%), barbiturates (0.35%), amphetamines (0.07%), PCP (0.03%). However, large variations are observed depending on the time of day, sex and age. For the covering abstract see ITRD E106992.