Performance Evaluation and Improvement Strategies: A Case Study of Lainchaur Intersection

Abstract

Traffic congestion at many intersections in the Kathmandu Valley remains severe despite various traffic control and management measures, and the Lainchaur Intersection, a three-legged junction, is one of the most affected. The congestion is mainly due to uneven traffic distribution, vehicle composition, and the absence of signal control. This study evaluates the operational performance of the intersection using microscopic simulation in PTV VISSIM based on traffic data collected over four days in July. Peak-hour morning traffic data (9:00 AM-11:00 AM) were obtained through videographic surveys and observed traffic volumes were converted into Passenger Car Unit (PCU) in accordance with Nepal Road Standards (2070). The simulation was conducted for all four days, with three days used for calibration and one day for validation to ensure reliability and accuracy. Performance was assessed using queue length, vehicle delay stop delay, and Level of Service (LOS). Results indicate severe congestion (LOS F) on major approaches, while minor movements operate under relatively better conditions (LOS A-C). As an improvement measure, fixed-time signal control based on the Webster method was evaluated under multiple cycle lengths (60 s, 80 s, 150 s, and 300 s), showing partial but inconsistent improvements. A future scenario with 7% annual growth indicates further deterioration, suggesting that fixed-time signal control alone may not be sufficient under future demand conditions, and adaptive or actuated signal control should be considered for improved operational efficiency.