Optimization of Signal Phase Setting to Improve Roundabout Intersection Performance: Case Study at Brawijaya Circle Intersection, Merauke

Abstract

Brawijaya Roundabout Intersection in Merauke Regency is one of the strategic urban intersections experiencing increasing traffic volumes, particularly during peak hours, which may lead to higher vehicle delays and queue lengths. This study aims to evaluate the operational performance of the intersection and analyze alternative signal phase arrangements to improve its performance. The analysis was conducted using the 2023 Indonesian Highway Capacity Guidelines (PKJI 2023) based on field survey data, including traffic volumes, intersection geometry, and existing signal settings. Since PKJI 2023 does not explicitly provide procedures for evaluating signalized roundabout intersections, several adjustments were applied to the analytical parameters, particularly regarding vehicle speed assumptions and the representation of intersection geometry, to better reflect local traffic characteristics. The performance evaluation considered capacity, degree of saturation, average delay, queue length, and level of service. Several alternative signal phase scenarios were developed and compared with the existing condition to determine the most effective configuration. The results indicate that signal phase arrangements significantly affect intersection performance. The optimize result reduced the degree of saturation, delay, and queue length while improving the level of service compared with the existing condition. The findings are expected to serve as a reference for the management of signalized roundabout intersections and support the application of PKJI 2023 under similar traffic conditions.