Abstract Manager

 HFST was implemented by the BC Ministry of Transportation and Infrastructure at several signalized intersections and off-ramps in the Lower Mainland and Vancouver Island in 2018 and 2019. These intersections and ramps had been selected based on their potential for safety improvement through an advanced identification and ranking methodology that considered all signalized intersections across the provincial highway network and high collision ramps.

 To estimate the safety effectiveness of the implemented HFST initiative, the Ministry carried out a rigorous before-and-after safety analysis. The analysis utilized a couple of cutting-edge methodologies for the before-and-after safety evaluation - the Empirical Bayes (EB) method and the Full Bayes (FB) method, to account for traffic exposure as well as various confounding factors, including history, maturation, and the regression-to-the-mean bias. The effect of HFST on safety was investigated by considering serious (fatal and injury) collisions, rear-end collisions, and collisions that occurred in wet road surface conditions. The results showed a statistically significant safety improvement at the treated locations. Specifically, the estimated reductions in serious collisions, rear-end collisions, and collisions in wet conditions are about 51%, 57%, and 64%, respectively.

 The HFST-paved sections have been performing well with no significant distresses such as aggregate loss or delamination. This initiative has resulted in sustainable and reliable improvements to road safety performance. Several lessons were learned from this project.  These lessons relate to the quality of materials to remedy performance issues, developing key messages early in the project to address public and media inquiries, the selection process of treatment sites, and the expected safety effectiveness.