Aggressive driving is a public-safety threat that often reflects displaced aggression, anger redirected from its original source. In traffic, anger can originate inside the vehicle (e.g., passenger conflict) or outside it (e.g., congestion). Driving's cognitive load and anonymity may facilitate such redirection. Personality traits; Negative Valence (antagonistic style), Neuroticism (affective reactivity), Agreeableness, and Conscientiousness may differentially shape these behaviors. This study examined the role of basic personality traits in predicting displaced aggression in traffic, distinguishing between aggression due to anger generated inside the vehicle (InsideDA) and outside the vehicle (OutsideDA). A total of 520 drivers completed a two-subscale traffic displaced-aggression measure (InsideDA, OutsideDA) and the Basic Personality Traits Inventory assessing six sub-dimensions: Agreeableness, Extraversion, Openness-to-Experience, Conscientiousness, Neuroticism, and Negative Valence. Correlations, multiple regressions, and manual dominance analysis were conducted to determine the relative importance of personality predictors. For InsideDA, dominance analysis indicated that Negative Valence was the strongest predictor (47%), followed by Neuroticism (28%), Agreeableness (18%), and Conscientiousness (7%). For OutsideDA, Neuroticism (38%) emerged as most influential, followed by Negative Valence (34%), Agreeableness (17%), and Conscientiousness (12%). Regression analyses converged on Neuroticism and Negative Valence as key positive predictors, with smaller protective effects of Agreeableness and Conscientiousness. These findings demonstrate that the origin of anger modulates the personality-aggression link: when anger arises inside the vehicle, displaced aggression is primarily driven by hostile interpretative tendencies (Negative Valence), whereas when anger originates outside the vehicle, it is best explained by emotional instability (Neuroticism). Low Agreeableness and Conscientiousness consistently amplified aggression, though to a lesser extent. Overall, results contribute to theoretical understanding of displaced aggression in traffic contexts and emphasize the practical importance of integrating personality-based risk factors into driver education, anger management interventions, and traffic safety policies.