Problem-drinker drivers who drank at multiple locations differ substantially from those who drank at only one location. Persons who drank at more than one location prior to their DWI arrest exhibit the most severe alcohol problems. Multilocation drinkers consumed significantly greater amounts of alcohol--for nearly all alcohol measures including consumption per drinking day, consumption averaged over 30 days, and consumption on the day of the DWI arrest--than single location drinkers. The multilocation group experienced more alcohol problems in their lives, had higher Mortimer-Filkins test scores, were intoxicated more frequently, and had a greater probability of a DSM-III-R alcohol-dependence diagnosis. Compared to the single location drinkers, the multilocation group had more bad driving incidents, frequently (once a week) drove while drunk, and expressed the attitude that the DWI had less of an impact on their lives. The findings suggest that multilocation drinkers require intensive interventions.