Study Details

Study Title: Safety effects of section control - An empirical Bayes evaluation

Authors: Høye

Publication Date:JAN, 2015

Abstract: The safety effects of section control were investigated at 14 sites in Norway. A before-after study was conducted with the empirical Bayes method in order to control for regression to the mean (RTM). Effects of trend, volumes, speed limit changes and speed cameras at some of the sites in the before period are controlled for as well. For injury crashes a non-significant reduction by 12% was found. The number of killed or severely injured was found to be significantly reduced by 49% at the section control sites. The results indicate that the crash reductions in tunnels (most of which are undersea tunnels with section control on steep downhill segments) are at least of the same magnitude as on open roads. The results are consistent with findings from speed measurements, although the crash reductions are larger than one would expect as a result from the speed reductions. Downstream of the section control sites (up to 3 km in each direction) injury crashes were found to be significantly reduced by 46%. The number of KSI downstream of the section control sites is too small for drawing any conclusions. It is concluded that section control is effective in reducing both speed and crashes, especially serious crashes, and that spillover effects (crash reductions at non-enforcement sites) are more likely to occur than crash migration. The size of the effects that were found should be interpreted with caution because of the relatively short after periods for some of the sites and the sensitivity of the results to the outcomes of individual crashes.

Study Citation: Høye,A. "Safety effects of section control - An empirical Bayes evaluation". Accident Analysis and Prevention, Vol.74,(2015)pp.169-178.


CMFs Associated With This Study

Category: Advanced technology and ITS

Countermeasure: Section Control

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.88122 StarsAllA,B,CAllRural
0.88122 StarsAllA,B,CAllRural
0.83172 StarsAllA,B,CAllRural
0.51493 StarsAllK,AAllRural
0.45553 StarsAllK,AAllRural
0.47533 StarsAllK,AAllRural
0.54463 StarsAllA,B,CAllRural
1.3-302 StarsAllK,AAllRural