There were two hypotheses for this study. The first was that driver violence would be predicted by the interaction of mild driver aggression and driving vengeance. Among highly aggressive drivers, driver violence would be greater for those that also reported elevated vengeance. The second was that driver violence would be predicted by the interaction of mild driver aggression and violations. Violence would be greater for drivers that reported elevated aggression, but only in combination with high levels of willful traffic violations. The study included 130 female and 74 male participants from the student and employee populations of a university from the metropolitan Toronto area. Measures employed for the study were the Driving Vengeance Questionnaire, Self Report Driver Aggression Questionnaire, Violent Driving Questionnaire, and Driving Behavior Questionnaire-Violation Subscale. The results demonstrate that mild driver aggression can represent a more enduring threat through the potential for escalation to more severe and dangerous driving behaviors. Acts of driver violence were more prevalent among a minority of drivers that typically exhibited elevated levels of mild driver aggression in combination with other dangerous driving attitudes and behaviors as part of their driving repertoire. Violence was more prevalent among male drivers that exhibited elevated levels of mild aggression in combination with heightened driving vengeance. While vengeful drivers have been found to exhibit greater aggression and violence in the driving environment, a vengeful attitude has also been liked to other forms of violent behavior. Driver violence was also predicted by the interaction of mild driver aggression and violations. Violent actions were greater among highly aggressive drivers, but only in association with elevated levels of willful violations. 3 figures, 2 tables, 61 references