Effect on road traffic injuries of criminalizing road traffic offences: a time-series study.

OBJECTIVE To determine the effect of criminalizing some traffic behaviours, after the reform of the Spanish penal code in 2007, on the number of drivers involved in injury collisions and of people injured in traffic collisions in Spain. METHODS This study followed an interrupted times-series design in which the number of drivers involved in injury collisions and of people injured in traffic collisions in Spain before and after the criminalization of offences were compared. The data on road traffic injuries in 2000-2009 were obtained from the road traffic collision database of the General Traffic Directorate. The dependent variables were stratified by sex, age, injury severity, type of road user, road type and time of collision. Quasi-Poisson regression models were fitted with adjustments for time trend, seasonality, previous interventions and national fuel consumption. FINDINGS The overall number of male drivers involved in injury collisions dropped (relative risk, RR: 0.93; 95% confidence interval, CI: 0.89-0.97) after the reform of the penal code, but among women no change was observed (RR: 0.99; 95% CI: 0.95-1.03). In addition, 13 891 men (P < 0.01) were prevented from being injured. Larger reductions were observed among young male drivers and among male motorcycle or moped riders than among the drivers of other vehicles. CONCLUSION The findings suggest that criminalizing certain traffic behaviours can improve road safety by reducing both the number of drivers involved in injury collisions and the number of people injured in such collisions.