Impact of the penalty points system on road traffic injuries in Spain: a time-series study.

OBJECTIVES We assessed the effectiveness of the penalty points system (PPS) introduced in Spain in July 2006 in reducing traffic injuries. METHODS We performed an evaluation study with an interrupted time-series design. We stratified dependent variables-numbers of drivers involved in injury collisions and people injured in traffic collisions in Spain from 2000 to 2007 (police data)--by age, injury severity, type of road user, road type, and time of collision, and analyzed variables separately by gender. The explanatory variable (the PPS) compared the postintervention period (July 2006 to December 2007) with the preintervention period (January 2000 to June 2006). We used quasi-Poisson regression, controlling for time trend and seasonality. RESULTS Among men, we observed a significant risk reduction in the postintervention period for seriously injured drivers (relative risk [RR] = 0.89) and seriously injured people (RR = 0.89). The RRs among women were 0.91 (P = .095) and 0.88 (P < .05), respectively. Risk reduction was greater among male drivers, moped riders, and on urban roads. CONCLUSIONS The PPS was associated with reduced numbers of drivers involved in injury collisions and people injured by traffic collisions in Spain.