Calibration of collision prediction models for unsignalized rural Albertan intersections

Thumbnail Image



Journal Title

Journal ISSN

Volume Title


University of New Brunswick


Alberta Transportation currently evaluates the safety performance of its facilities by collision frequency or rate, which is not an accurate or reliable method. This project seeks to assist in optimizing road safety resources at locations where the best value and the most improvement can be realized. Calibration of the Highway Safety Manual's collision prediction model yields factors that can be used to provide more accurate collision modeling for the province. The possibility for a sub-regional calibration is also explored and excluded after it was found to not produce significantly different results. Though constrained to rural undivided unsignalized intersections, this process lays the foundation for the calibration of collision prediction models for additional facility types. The results of this study produced calibration factors of 1.254 for three-legged intersections, and 0.721 for four-legged intersections. It was determined that there was no statistically significant difference in calibration factors intra-provincially between Alberta Transportation's (AT) administrative regions, or areas with different environmental characteristics. The calibration factors resulting from this project are to be used to provide predictive capability to AT's infrastructure management systems, and to facilitate the safety screening of intersections.