Traffic congestion, driver stress, and driver aggression

Drivers were interviewed over cellular telephones in high- and low-congestion conditions during a single commute. During each interview, state measures of driver stress and driver behaviors were obtained. Behavior responses were subdivided into six categories: aggressive, information seeking, planning, minor self-destructive, distraction, and relaxation techniques. Both state driver stress and aggression were greater in high- than in low-congestion conditions. No other behavior category differed between low and high congestion. Multiple regressions were calculated to determine the predictors of state driver stress. In low congestion, time urgency predicted state driver stress, while aggression predicted driver stress in high congestion. In both conditions, a trait susceptibility toward viewing driving as generally stressful was predictive of state driver stress levels, which further strengthens the use of the Driving Behaviour Inventory—General as a predictor of “trait” driver stress. Females and males did not differentiate on state stress or any behavior category. Aggr. Behav. 25:409–423, 1999. © 1999 Wiley-Liss, Inc.