Traffic Congestion Evaluation at the Unsymmetrical Signalized Intersection of Sentul, Yogyakarta

Sentul intersection is the unsymmetrical signalized intersection located nearby the Sentul Market of Yogyakarta, which has a potential causing traffic congestion. The study aims to analyze the performance of an unsymmetrical intersection based on Indonesian’s regulation and to determine the congestion cost occurred at the Sentul signalized intersection. This study utilizes a quantitative method to evaluate the intersection performance by considering delay, vehicle queue, congestion cost, and level of service (LOS). The study included primary data collection from a traffic survey, a traffic modelling to assess the intersection performance, and a congestion cost analysis using software by considering three different conditions: Existing Condition, Alternative 1 and Alternative 2. The results showed that the performance of the existing condition was very poor with average delay of 106.71 second/vehicle, queue time of 134.42 seconds, LOS of F, and congestion cost of intersection was IDR 3,722,627 per hour. The 1 st alternative was re-designing phase time of traffic light and the 2 nd alternative involved re-designing green time, widening of approach area, applying left turn on red (LTOR) for the west-arm of intersection, and removing on-street parking area. The 2 nd alternative is the best solution since it will reduce delay by 30 %, vehicle queue by 54 %, congestion cost decrease by 50 %, the LOS increase from F to E, and then improve intersection performance significantly.