OBJECTIVE: To examine the association between drinking patterns and alcohol-related traffic casualties. STUDY DESIGN: Data linkage of cross-sectional survey data on alcohol consumption with official traffic casualty records. METHODS: Alcohol consumption measures for usual heavy drinking and risky single occasion drinking were derived for different time segments of the day from a 7-day drinking diary study of 747 current drinkers. Measures were correlated with official records of alcohol-related traffic casualties. RESULTS: There was a high correlation between alcohol-related traffic casualties and the number of risky single occasion drinkers that consumed alcohol outside their homes (r=0.92). On average, about 50% of these drinking occasions were attributed to usual moderate drinkers. The proportion of usual heavy drinkers was lowest in the time segments with the most alcohol-related casualties. CONCLUSION: Preventive countermeasures should be targeted at the general population, enforced particularly during specific periods of the week.