Among the many risk factors that contribute to young drivers' crash involvement, two are critical: peer passenger presence, which is unique to young drivers, and the influence of alcohol, a universal risk for drivers but one against which young drivers are most susceptible. Clarification of how passenger presence interacts with alcohol consumption to increase risk is needed. The impact of experimentally manipulated passenger characteristics and alcohol quantity on risky driving is observed using driving simulation and a random assignment experimental design with a sample of 18-21 year old male and female drivers.

Inclusion Criteria:

• being 18 to 21 years of age (18 years old is the legal age for alcohol consumption in the province of Quebec)
• past experirence with drinking at least 2 alcoholic beverages in one episode
• having a provisional driving license
• driving in the past 3 months

Exclusion Criteria:

• health problem that contraindicates participation
• pregnant or breastfeeding
• signs of problem drinking
• positive BAC or recent drug use measured at arrival