Evaluation of Saturation Flow During Green Time Interval Using the Time-Slice Method Based on PTV VISSIM Microscopic Simulation

Abstract

Traffic congestion in urban areas poses a serious challenge to the operation of an effective and efficient transportation system. One of the main problem areas is at signalized intersections, such as the Tohpati Intersection in Denpasar, which experiences high levels of congestion due to green light timing that is disproportionate to the actual vehicle volume. This study aims to evaluate the impact of changes in phase and green time on saturation flow and intersection capacity using the time-slice method and microscopic simulation with the assistance of PTV VISSIM software. The time-slice method was used to divide the green time interval into short 5-second segments, which were then analyzed to obtain key parameters such as start-up lost time, peak flow, and decay flow. Simulation data were validated using the GEH test to ensure the model’s consistency with real-world field conditions. The results show that an optimal green-phase timing scenario can reduce queue length by more than 85% and decrease vehicle delay by more than 90% compared to existing conditions. The integration of the time-slice method and VISSIM modeling proved effective in representing traffic characteristics and provided a strong foundation for technical recommendations aimed at the sustainable optimization of intersection performance.