Association of a few interventions by police with changes in traffic injuries in Iran

In this study we investigated the efficacy of provisional driver licensing and mandatory seat belt use legislations on reducing traffic injuries and the intensity of injuries (fatal or nonfatal). Data on traffic accidents and injuries from one year before till two years after the implementation of provisional driver licensing and mandatory seat belt use legislations were obtained from police. After data cleaning and stratification traffic injuries and mortalities from one year before till two year after the implementation of graduate driver licensing compared in those in early years of their driving experience. In addition, to evaluate the efficiency of mandatory seat belt use legislation the intensity of traffic injuries (proportion of deaths) were compared. Drivers under 23 years of age consisted 22. 8% of total accidents in the prior to the implementation of graduate driver licensing. This proportion reduced to 15. 5% and 16. 1% in the first and second year after implementation, respectively, in holders of provvisional B1 type driver license. This approximately 7% reduction in total accident was statistical significant (p<0.001). Regarding the intensity of injuries after the implementattion of the mandatory seat belt use, our findings showed that traffic mortalities consisted of 13. 3% of all traffic accidents in the year prior to the implementation, while this proporttion decreased to 9.9% and 1111.5% in the first and second years after the implementation, respectively. Our findings suggested that both interventions were efficient in reduction of intensity of traffic injuries and provisional driver licensing was also efficient in reducing the crude number of traffic injuries.