In Côte d'Ivoire alcohol and drugs consumption in the general population is a serious issue. However, their role in Road Traffic Accidents (RTAs) has never been investigated. Our study aimed to estimate the prevalence of alcohol-impaired road users at the time of the RTA and report psychoactive drug use, in various categories of casualties, and in various circumstances of the crash. We conducted a cross-sectional study including 893 casualties involved in fatal or non-fatal RTAs and admitted at the Emergency Room or the Forensic Institute from March to September 2012. Blood alcohol dosage (BAC) and urine drug screening were carried out, and results were linked with hospital and police crash report data. The mean BAC in positive cases indicated heavy drinking before the crash: drivers (1.9 g/L), pedestrians (2.1 g/L), passengers (1.5 g/L). The prevalence of alcohol-impairment was significantly higher in drivers (41%) and riders (27%) compared to pedestrians (17%) and passengers (13%). Over 75% of casualties that tested positive for alcohol had a BAC largely above the legal limit. Psychoactive drug use was twice more prevalent in alcohol-impaired drivers than in sober drivers (20% vs 10%). Binge drinking is an emerging issue in African countries, which should be taken into account in the management or prevention of road traffic injuries.