Modelling Urban Traffic Flow and Congestion Patterns Using Simulation Tools: A Study of Surulere, Lagos

Traffic simulation modelling offers planners and transport managers powerful tools for understanding congestion dynamics and evaluating the impact of interventions before physical implementation. This study develops and validates a traffic flow simulation model for the Surulere Local Government Area of Lagos, one of the densest and most congested urban environments in the South West zone. The study employs the VISSIM microsimulation platform, calibrated with traffic count data collected at 12 junctions over a 10-day period during morning and evening peak hours. The model incorporates intersection geometries, signal timing, pedestrian crossing volumes, and vehicle composition data. Simulation outputs are validated against observed travel time surveys conducted on three arterial routes. The calibrated model is then used to evaluate four congestion management scenarios: signal timing optimisation, a one-way road conversion at two critical junctions, a pedestrian bridge at a high-conflict crossing, and a partial road widening scheme. Results show that signal timing optimisation alone can reduce average network delay by 16 percent at minimal cost, while the one-way conversion offers the most significant congestion reduction at 29 percent but requires property acquisition. The pedestrian bridge improves safety metrics without affecting vehicle delay. The study demonstrates the value of simulation modelling as a planning tool for Nigerian transport authorities and provides a replicable methodology for congestion analysis in high-density urban areas. Keywords: traffic simulation, VISSIM, urban congestion, Lagos, signal optimisation.