Advancing Urban Mobility: A Microsimulation-Based Approach for Assessing the Impact of Intersection Improvement Strategies in Qatif, Saudi Arabia

Today urban metropolitans worldwide are facing significant mobility challenges, where congestion, delays, and safety concerns hinder quality of life and sustainable growth.Like other developing nations, traffic congestion has emerged as a major socio-economic in main cities around Saudi Arabia.Intersections serve as hotspots for traffic congestion and incidents.To address the operational inefficiencies and safety concerns at intersections, it is essential to evaluate the intersection improvement strategies through data-driven and simulation-based methods.The current study aims to assess the operational and safety performance of various improvement strategies for two critical signalized intersections (Nabiyyah Bridge and Uhud Street) along the Dhahran-Jubail Highway in the city of Qatif, Saudi Arabia.A comprehensive evaluation framework consisting of field data collection through manual observations, advanced video analytics, and microscopic simulation modeling with PTV VISSIM is proposed.In addition to simulating the existing/baseline conditions, three improvement scenarios (optimized signal retiming, (2) targeted geometric modifications, and (3) conversion to a diverging diamond interchange) were tested.Modeling results demonstrated that signal retiming/optimization alone reduced average vehicle delays by up to 35% and improved the Level of Service (LOS) from E/F to C/D.Geometric enhancements consisting of adding exclusive left turns and improved channelization further delivered reductions in queue length and average vehicle delay.The third scenario of conversion to diverging diamond interchange (DDI) yielded only marginal additional benefits primarily due to local traffic patterns and spatial constraints.Safety analysis and crash estimation through Highway Safety Manual (HSM) methodologies revealed that operational improvements were correlated with a ZKG INTERNATIONAL