Improving Roundabout’s Level of Service (A Case Study of Kecil Roundabout in Palangkaraya)

Abstract

Kecil Roundabout is a signalized roundabout located in Palangkaraya. Traffic jams occur during the rush hour because the intersection is in the central education and office area and has become the main access for the community traveling for their daily activities. This study was done to analyze the performance of the existing roundabout and determine the most suitable type of intersection with life-cycle cost analysis (LCCA) suggested by IHCM (Indonesian Highway Capacity Manual). Primary data were obtained by a direct survey, including the traffic volume of the intersection, intersection and roundabout geometry, signal time, and saturation flow time slices. The methods used are the Indonesian Highway Capacity Manual (IHCM) 1997 and the saturation flow approach. The result of performance analysis on the existing intersection condition with the saturation flow method shows that the average delay is > 60s/pcu (service level F). Based on the scenario analysis, scenario 1 (a signalized roundabout) provides service level D, scenario 2 (intersection without roundabout) gives a service level almost reaching C, and scenario 3 (enlarged roundabout) has a degree of saturation (DS) < 0.8. The calculation with life-cycle cost analysis (LCCA) has the result that the best fitting type of intersection corresponding to the existing traffic volume is an elevated interchange.