Aggressive driving: a preliminary analysis of a serious threat to motorists in a large metropolitan area.

OBJECTIVE Aggressive driving is consistently rated as the leading concern of motorists in our metropolitan area, ahead of even "drunken driving." Few objective data exist on the incidence of aggressive driving. The purpose of this study was to determine the incidence of selected aggressive driving behaviors and to establish a baseline for future interventions and research. METHODS Speeding, traffic signal violations ("red-light running"), and stop-sign violations were studied. Speeding data were recorded by inductance loops embedded in major roadways (n = 10). Data were collected from red-light cameras (n = 73 cameras, 82 sites) and by trained observers at intersections with traffic signals (n = 15) or stop signs (n = 15). Data included total traffic volume, numbers of violations, and each violator's speed. RESULTS The majority of motorists on major roadways drive at speeds exceeding the speed limit and between 40% and 80% of vehicles were traveling at 10 mph or more over the speed limit. Red-light running occurred at equivalent rates both by camera (1.5 violations/1,000 vehicles) and by observer (1.3 violations/1,000 vehicles). The absolute numbers of red-light violations were extremely high (approximately 30,000 per month), and 16% violated the signal at > 10 mph above the speed limit. The incidence of "at-speed" (i.e., without slowing) stop-sign violations was dramatic (17.5 violations/1,000 vehicles). These were confirmed by video review and represent high risk for crashes. CONCLUSION Aggressive driving behaviors are frequent and often include very dangerous actions. Currently available deterrents appear to have limited impact in our congested area. Inadequate resources for enforcement and limited public awareness may be partially responsible. We have adopted a multidisciplinary approach to this serious problem including public education, stepped-up enforcement, and psychological treatments.