Study Details

Study Title: Evaluating the Effectiveness of the Safety Improvement Program in Saskatchewan Using an Observational Before-After Study with the Full-Bayes Approach

Authors: Sacchi and Tayebikhorami

Publication Date:JAN, 2021

Abstract: A key step in highway safety management is to determine whether the frequency and/or severity of collisions have been reduced after implementing a specific improvement program. This research focused on evaluating the safety performance of 50 sites that have been improved under the Saskatchewan Ministry of Highways and Infrastructure’s (MHI) Safety Improvement Program (SIP). SIP projects were designed to reduce the frequency and severity of collisions on provincial highways in rural areas through the implementation of different safety countermeasures. The methodology adopted was an observational before-after study with the full Bayes approach. The results showed that SIP projects reduced total collisions by 14.8% and severe (fatal-plus-injury) collisions by 25.4%. The reduction of property-damage-only collisions was not found to be statistically significant. Crash modification factors (CMFs) for the two most frequent SIP treatments, i.e., right-turn lanes and delineation lighting at intersections, were estimated and compared to the results of the literature.

Study Citation: Sacchi, E. and S. Tayebikhorami. "Evaluating the Effectiveness of the Safety Improvement Program in Saskatchewan Using an Observational Before-After Study with the Full-Bayes Approach". Canadian Journal of Civil Engineering, (2021).

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Highway lighting

Countermeasure: Install intersection lighting

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.79220.84 StarsAllAllAllRural

Category:Intersection geometry

Countermeasure: Install right-turn lane

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.83416.63 StarsAllAllAllRural