A before-after study of section control at 14 sites in Norway found a reduction of injury crashes by between 12 and 22% and a reduction of the number of killed or severely injured road users by between 49 and 54%. Downstream of the section control sites (3 km in each direction) injury crashes were found to be reduced significantly by 46%. The study has controlled for trend effects, volumes, speed limit change at some of the sites and speed cameras at some of the sites in the before period. Regression to the mean is controlled for by using the Empirical Bayes method. Eight of the section control sites are in tunnels. The results indicate that the crash reductions in tunnels are at least of the same magnitude as on open roads. (Author/publisher)
Abstract