This study determined whether convicted impaired drivers differed from undetected impaired drivers and whether these two groups differed from drivers who had not recently driven impaired. Convicted drivers were recruited from bars, courts and remedial or DWI education courses while remaining subjects were recruited from bars. Convicted drivers experienced more accidents and infractions, drank more on a given occasion, showed more symptoms of problem drinking and scored higher on measures of assaultiveness and depression. Both groups of impaired drivers were more externally controlled, resentful, verbally hostile, impulsive and self-deprecative. The results suggest that impaired drivers are a deviant group characterized by personal maladjustment and heavy alcohol consumption.