Assessing the impact of express lanes on traffic safety of freeways

The rise of Express Lanes also known as High Occupancy Toll (HOT) Lanes and Managed Lanes, signifies a major leap in traffic management and transportation funding. Despite their increased deployment to ensure reliable travel times through dynamic tolling during peak traffic periods, a comprehensive evaluation of their safety impact is notably lacking. Presently, the Crash Modification Factors Clearinghouse, a vital resource, only lists two case studies related to Express Lanes, one of which is our own research. This lack of data highlights the critical need for more extensive studies to thoroughly assess the safety benefits of Express Lanes and to improve their application. This study aims to rigorously evaluate the safety impact of express lanes on freeways, presenting a first-of-its-kind, in-depth analysis of their specific effects on both Express Lanes and General-Purpose Lanes (GP-Lanes) individually. The analysis utilized data from 55 miles of Express Lanes across various locations in Florida, comparing them to High Occupancy Vehicle (HOV) lanes. The results demonstrate that converting HOV lanes to Express Lanes or introducing new ones does not compromise overall freeway safety. In fact, safety within Express Lanes improves, as evidenced by a decrease in crash occurrence and Crash Modification Factors for Express lanes, which are below "1" across all crash categories. This underscores the effectiveness of Express lanes in enhancing roadway safety. In contrast, incidents in GP-Lanes have increased, indicating a shift of crashes to these lanes, and thus making Express lanes relatively safer. This underlines the importance of continued research into the safety impact of express lanes and calls for further studies to refine traffic management strategies, aiming at enhancing travel efficiency while ensuring traffic safety, especially for the GP-Lanes amid the expansion of express lanes.