Evaluating Intelligent Traffic Management and Intersection Performance at Ring Road Kileleshwa/Riverside Drive, Nairobi

Abstract

This study evaluates the impact of Intelligent Traffic Management Systems (ITMS) on the operational performance of the Ring Road Kileleshwa/Riverside Drive intersection in Nairobi City, Kenya. Despite increasing deployment of ITMS in African cities, microsimulation-based evaluations of their operational effectiveness remain limited. Using AIMSUN microsimulation software, four traffic control scenarios were modelled and analysed: unsignalized priority control, fixed-time signals, optimized fixed-time signals, and vehicle-actuated signals. Performance was assessed using throughput, volume-to-capacity ratio, delay, queue length, and Level of Service (LOS). Results indicate that all scenarios experienced severe congestion, although operational performance varied across approaches. Vehicle-actuated control increased throughput but worsened delays due to unoptimized base timing, while the optimized fixed-time plan achieved the most balanced operational performance. The findings demonstrate that signal optimization alone cannot resolve physical capacity constraints and must be complemented by geometric improvements. The study contributes a replicable microsimulation framework for evaluating ITMS effectiveness in African urban intersections.