Road Safety Effects of Speed Enforcement: A Case-Study in Flanders.

Abstract

This paper analyzes the effects on road safety of speed enforcement on a main road in the province of Vlaams-Brabant (Flanders). After a descriptive accident analysis, carried out by the provincial government in the late nineties, the 'N8' wasselected as one of the most unsafe roads, mainly with regard to speeding violations. By the end of 2002, a comprehensive speed enforcement programme was set up for the N8. The speed enforcement strategy consists of increased police control, installation of automated speed cameras, reduced speed limits and information campaigns. Taking into account accident data of a 12 year pre-period and 3 year after-period, this study shows that the effect of the programme on the number and severity of road accidents, adjusted for the trend and regression-to-the-mean, is significant. The empirical analysis reveals a reduction of 35% for the total number of accidents, 43% for the total number of accidents minus the collisions with parked vehicles, 25% for accidents with material damage only, and 19% for injury accidents. This study also takes a closer look at the impact of different post-implementation periods using accident data of 1 or 3 years after the implementation of the speed enforcement programme on the calculated effectiveness results and warns for severe overestimation when a one-year period is used.