Run-off-Road Vehicle Collision Risk Assessment for Highway Bridge Networks in Ontario

In 2019, Ontario recorded 13,890 collisions between motor vehicles and fixed objects, resulting in 65 fatalities, 2174 injuries, and 11,651 instances of property damages. A significant concern arises from heavy vehicles veering off the road in high-speed environments, posing a substantial threat to overpass bridge structural safety. This study aims to examine the run-off-road (ROR) vehicle collision risks of highway bridge networks and to identify the critical bridges within the network. Currently, the scheduling of bridge maintenance and repair relies solely on the bridge condition rating system. While this system is beneficial, it does not account for the safety risks to bridges from extreme events, such as vehicular collisions, nor does it consider the broader implications of a bridge's functional loss on the transportation network. This study proposes a multiscale risk-based assessment framework to prioritize bridges for rehabilitation in response to ROR vehicle collisions. This framework assesses not only the probability of collision and the structural condition of individual bridges but also their criticality within the entire network. It incorporates multilevel criteria, including both component-level indices and network-level topology measures. Applying this framework to a highway bridge network in Ontario as a case study, the findings suggest that the overall bridge network faces a medium-to-low risk of collision. The bridges that feature high transportation criticality in the investigated network are generally in good condition and capable of withstanding potential vehicle collisions. The practical application of this study provides guidance for prioritizing maintenance efforts for highway bridges within budget constraints.