Assessment of Traffic Performance of Signalized Intersection Using HCM 2010 and VISSIM-Based Microsimulation (Case study Dodoma City, Tanzania)

Abstract

Traffic conditions within urban road networks are largely determined by the operational efficiency of intersections, particularly those controlled by signals. The Area D intersection in Dodoma City, Tanzania, experiences considerable congestion during peak periods, leading to significant delays for road users. This study assesses the operational performance of the intersection using the Highway Capacity Manual (HCM 2010) and microsimulation modelling with PTV VISSIM during morning (06:00–10:00) and evening (4:00–6:00) peak periods.Traffic composition includes light vehicles, motorcycles, and heavy vehicles, with motorcycles forming a significant share. HCM analysis indicates average delays of 55.16 sec/pcu (morning) and 115.14 sec/pcu (evening), corresponding to Levels of Service (LOS) E and F, respectively. VISSIM results show higher delays, confirming critical congestion conditions.Three improvement scenarios were tested, with the third  combining signal timing optimization and geometric modifications proving most effective. This scenario reduces delays to 21.27 and 29.86 sec/pcu and improves LOS to B and C during morning and evening peaks. This alternative reduced delays, minimized queue lengths, and enhanced LOS to acceptable levels.