Objective: It was hypothesized that the combination of self-reported aggressive behaviors committed by the driver himself/herself (oselfo scale) and perceiving himself/herself as an object of other drivers' aggressive acts (oothero scale) increases road accident involvement risk across gender and countries. The aim of this study was, therefore, to investigate this symmetric relationship between aggressive driving of self and other and its relationship on accident involvement among British, Dutch, Finnish, and Turkish drivers. Methods: Survey studies of 3673 drivers were carried out in four countries; that is in Finland, Great Britain, The Netherlands, and Turkey. Analyses were conducted separately for men and women. Results: Overall, the interaction among aggressive warnings, hostile aggression, and revenge factors indicated that aggressive warnings might have a potential to release anger and escalate aggression both owithin driverso and obetween drivers.o Symmetric interpersonal aggression between aggressive warnings and hostile aggression and revenge factors of self and others created a serious risk for road accident involvement in every country except among British male and Finnish female drivers. Conclusions: The other driver's aggressive behavior is significantly associated with increased accidents, except for Turkish male drivers. It seems that another driver's aggressive behavior can be important in predicting crasheseven more important than aggressive behavior on the part of the driver him- or herself.