Adoption of Highway Safety Manual Predictive Technologies for Canadian Highways

This paper is based on recent research projects for Transport Canada and the Ministry of Transportation that assessed implementation requirements for the Highway Safety Manual (HSM) predictive methods. It serves partly as an illustration of what it takes for jurisdictions to assess their implementation requirements. The focus is on two applications of predictive methods: a) evaluation of the safety impacts of alternate design scenarios using an algorithm that applies baseline safety performance functions (SPFs) and collision modification factors (CMFs) and b) estimation of the safety benefits of proposed or implemented countermeasures. For the first application, the transferability of the HSM algorithm for urban signalized intersections in Toronto is explored by assessing both the base SPFs and CMFs. In general, the recalibration exercise was successful. However, for individual variables, there is some bias indicating that the CMFs could be improved upon. For the second application, an SPF knowledge base was developed to enable the selection by Canadian jurisdictions of the appropriate SPF for a specific countermeasure and site type. These crash type SPFs, would be used in the economic appraisal of contemplated countermeasures and in the evaluation of implemented treatments. The use of a spreadsheet developed to facilitate the SPF selection process is illustrated. For the covering abstract of this conference see ITRD number 201211RT334E.