Moving (More) People Safely: Examining the Safety Impacts of HOV Lanes

High-occupancy vehicle (HOV) lanes are designed to increase the passenger-carrying capacity of roadways by requiring that all vehicles using the HOV lanes be occupied by a minimum number of passengers (e.g., the driver plus, at least one additional passenger). HOV lanes, in various forms, have been in use across North America for several decades. However, there is little information available with respect to their impact on the safety performance of the roadways to which they have been added. Over the past ten years, HOV lanes have been added to several freeway facilities in the Greater Toronto and Hamilton Area (GTHA), and analysis was recently undertaken to examine how the HOV lanes have impacted safety on the treatment sections of those roadways. Predictive collision analysis was used to calculate collision modification factors (CMF) for the addition of buffered, limited-access, concurrent flow HOV lanes to a simple, controlled-access freeway. Related, trends in collision activity have also been identified, as have areas for potential future study. Based on the CMF development and collision trend analysis, the general conclusion that can be reached is that the addition of buffered, limited-access, concurrent flow HOV lanes to a simple, controlled-access freeway can be expected to result in a moderate (15%) increase in overall collision frequency. The increase in collisions consists almost entirely of additional property damage only (PDO) collisions, particularly rear-end collisions, freeway congestion and several HOV lane design elements appear to be contributing factors.