Performance Evaluation and Improvement of an Intersection - A Case Study of Thapathali Intersection

Abstract

The Thapathali intersection located in Kathmandu Valley is a crucial junction connecting the city to Lalitpur and other major intersections like Maitighar and Tripureshwor. Given its high traffic volume, there is a need for a detailed analysis of the current operational performance of the intersection and the exploration of new solutions to improve its efficiency. A video-based survey was conducted over a period of 5 days including 3 weekdays and 2 weekends to gather data. The manual vehicle count was performed using custom manual counting software and the data was analyzed. The average peak hour traffic volume during the weekdays was 5,598 PCU in the morning and 4,886 PCU in the evening, while the weekend traffic volume was 4,697 PCU in the morning and 4,597 PCU in the evening. On average, motorcycles constituted 70.58% of the total traffic. The simulation model of the intersection was developed using the traffic analysis software SIDRA for both weekdays and weekends. After the models were calibrated and validated using the 95th percentile back of queue (BoQ), the performance of the intersection was evaluated under the current traffic policed controlled scenario. The analysis revealed average delays of 99.6 seconds/vehicle and 35.1 seconds/vehicle for weekdays and weekends respectively, with level of service (LoS) F and D under HCM 2010 and average speeds of 16.6 kmph and 24.7 kmph respectively.