Operational Analysis and Capacity Improvement Strategies for Signalized Intersections: Case Study on Miami, Florida

Urban population growth and expanding economic activity have intensified the demand on transportation networks, resulting in higher traffic volumes, increased spillbacks, and a declining level of service (LOS). Signalized intersections, as critical components, play a vital role in managing urban congestion. This study examines a heavily congested intersection in Miami, Florida, using Highway Capacity Software (HCS7) to assess operational performance and test improvement strategies. The baseline analysis revealed excessive delays, severe queue spillbacks, and LOS F during the PM peak period. Two data-driven scenarios were evaluated: (1) signal timing optimization, and (2) a combined approach involving both optimized timing and a proposed grade-separated pedestrian bridge. Scenario 2 achieved the most significant performance gains by reducing average delays by approximately 53% and improving the intersection’s LOS from F to E. Beyond operational benefits, the pedestrian bridge is supported by crash reduction evidence (CMF), complies with Americans with Disabilities Act (ADA) standards, and promotes long-term urban sustainability. The study’s methodology offers transferable insights for similar urban intersections facing high demand and multimodal conflict.