THESIS ABSTRACT

Abstract

Motorization in Southeast Asia has developed rapidly over the last few decades. Despite of their lower performance at high volume intersections, roundabouts have emerged as a superior solution for reducing severe crashes. This study aimed to Assess traffic performance of Buddha Chowk roundabout intersection in Hetauda, Makawanpur and evaluate alternatives for improving the performance parameters. The analysis focused on evaluating the level of service (LOS), delays, queue lengths, and the number of conflicts. Traffic videography surveys and field measurements were conducted for data collection. An Aimsun Next (version 2024.0.1) micro-simulation model was developed, calibrated, and validated to reflect the current traffic conditions and evaluate the intersection's performance. The model was used to analyze four improvement alternatives: Alternative I (Geometric (Grade) improvement), Alternative II (Expansion of roundabout and approaches), Alternative III (Signalization), and Alternative (Grade separation). The evaluation considered both base- year traffic and forecasted traffic scenarios for 5-year and 10-year projections. For the base year, all four alternatives showed improvements over the existing scenario, with Alternative IV offering the most significant benefits with LOS B, a delay of 14.76 seconds, an average maximum queue length of 22.60 meters, an average operational speed of 35.63 kmph, and 123 total conflicts. For the 5-year forecasted traffic, Alternative IV is the best, with the LOS D. It results in an average delay of 24.74 seconds, an average maximum queue length of 50.27 meters, a total of 204 conflicts, and an average operational speed of 29.48 km/h. For the 10 years, the LOS for all alternatives has consistently remained at LOS F. Therefore, it may be beneficial to explore alternative solutions, such as four-lane grade-separated intersections, to improve traffic flow and efficiency.

Keywords

Calibration, Validation, LOS, Delay, Queue length, Operational speed