The present research verified the psychometric properties of the Driving Anger Expression Inventory (DAX; Deffenbacher, Lynch, Oetting, & Swaim, 2002) on a Romanian sample (n = 262). Exploratory factor analysis revealed a three-factor structure: Verbal and Physical Aggressive Expression (α = .86), Adaptive/Constructive Expression (α = .88) and Using the Vehicle for Aggressive Expression (α = .83). The aggressive forms of expressing anger were summed up in the Total Driving Aggressive Expression Index (α = .90). Confirmatory factor analysis supported the three factors solution, by showing a good fit into a 30 items version of the DAX. All the aggressive forms of anger expression correlated positively with each other and with trait Aggression-Hostility, while the adaptive way of expressing anger correlated negatively with them, thus supporting the convergent validity of the DAX. Age differences were identified, in that younger drivers scored higher in Using the Vehicle for Aggressive Expression scale and in Total Driving Aggressive Expression Index, while older drivers scored higher in Adaptive/Constructive Expression scale. Several directions for future research concerning the DAX are suggested. Overall, our results showed that the Romanian version of the DAX is a valid tool for assessing aggressive driving.