Multimodal Injury Risk Analysis Between Road Users at Signalized and Nonsignalized Intersections

This paper proposes a multimodal approach to study safety at intersections by simultaneously analysing the safety and flow outcomes for both motorized and non-motorized traffic. This study uses an extensive inventory of signalized and non-signalized intersections on the island of Montreal, Quebec, Canada, containing disaggregate motor-vehicle, cyclist and pedestrian flows, injury data, geometric design, traffic control and built environment characteristics in the vicinity of each intersection. Bayesian multivariate Poisson models are used to analyze the injury and traffic flow outcomes and to develop safety performance functions for each mode at both facilities. After model calibration, contributing injury frequency factors are identified. Injury frequency and injury risk measures are then generated to carry out a comparative study to identify which mode is at greatest risk at intersections in Montreal. Among other results, this study identified that the number of injuries is greatest for motor-vehicles, but when exposure is accounted for, in the risk measure, this reveals that motor-vehicles are exposed to much smaller risks than any other mode, for both types of facilities. This highlights the need for safety improvements for non-motorized users who are, on average, at 17 to 28 times greater risk than motorists at signalized intersections and 2 to 19 times greater at non-signalized intersections. Also revealed, at signalized intersections pedestrians are most at risk and at non-signalized intersections cyclists are most at risk. Motor-vehicle traffic is the main risk determinant for all injury and intersection types. Also, the existence of correlation between flows, injuries and risks were tested.