Investigating Approaches to Advancing Knowledge on the Effects of Road Safety Treatments: An Application to Ontario Rural Two-Lane Highways

Crash modification factors (CMFs) are important tools for understanding the safety benefits of treatment options. However, CMFs typically lack variability as they apply a single factor to all the sites that are treated by these road safety measures. Crash modification functions (CMFunctions) are one way to capture the variability of CMFs as a function of independent variables. This research conducted a case study on the application of edgeline, centreline and dual rumble strip treatments on Ontario provincial highways and investigated CMF variability by developing CMFunctions as well as separate CMFs for tangent and curved sections. Curved sections experienced greater benefits from the application of the rumble strips. In conducting the study, the Highway Safety Manual’s application of rumble strip CMFs to Ontario roadways was also explored.