This report has evaluated the reduction in crash involvement of cars equipped with Electronic Stability Control (ESC) systems. The evaluation has been conducted for all crashes as well as for a variety of road and loss of control conditions. In addition, a study of ESC benefits in terms of crash costs and accidents prevented has been undertaken. The results show that ESC effectiveness is 7% in crashes of all severity. Serious crashes are 11% lower compared to non ESC cars and fatalities 25% lower. The potential savings in accident costs for a 100% take up of ESC amounts to some 959 million pounds by preventing some 7800 crashes. Even at a 50% take up the saving amounts to some 480 million pounds. ESC appears to offer additional benefit in adverse road conditions. Overall effectiveness was estimated as 20% for icy conditions and 9% for wet conditions compared to 5% for dry roads. In terms of serious crashes however, ESC effectiveness appears even more pronounced, 22% for wet roads compared to 3% for dry. Skidding and overturning crashes are typical situations on bends when the driver enters too quickly and attempts to steer. The study suggests a high ESC effectiveness 23% in all skidding related crashes and 36% in all overturning crashes. The corresponding values for serious crashes are 33% and 59% respectively. There appears to be little difference in effectiveness depending on whether a male of female is driving but effectiveness is serious side crashes is much higher (22%) compared to that in serious frontal crashes (2%). Single vehicle crashes are those where ESC is often supposed to have the greatest effect. Compared to non-ESC cars, 27% fewer ESC vehicles were involved in all single vehicle crashes compared to 7% for multi and single vehicle crashes taken together. Unfortunately case numbers did not allow a reliable assessment of ESC contribution to the reduction in serious single vehicle crashes. Overall, ESC has shown worthwhile reductions in both accident frequency and cost across a wide variety of crash situations. (Author/publisher)
Samenvatting