Performance Analysis of Roundabouts using SIDRA: A Micro-Analytical Software

Abstract

Intersections affect the safety and capacity of urban traffic. Therefore, the design and selection of the type of intersection need to be made very carefully. According to the demand level, a different intersection can be designed. Modern roundabouts are one of the types of circular intersections that provide advantages over other types of intersection in terms of smooth operation and safety. Modern roundabouts exist in several types today worldwide. In practice, the distinction about the kinds of roundabouts would not be fully clarified; as a result, queuing and delay can be seen as negative effects. The aim of this study was to analyze the operational performance of the roundabout at Jalan Mutiara Emas Utama in Mount Austin, Johor Bahru, during peak hours. The traffic volume was also measured for a 1-hour peak-hour period in the morning and evening. The geometric data and performance of roundabouts in the year 2020 were taken from Majlis Bandaraya Johor Bahru (MBJB). and analyzed using the SIDRA version 9 software. As result the performance analysis indicated that the demand flow of vehicles at the south lanes, Jalan Mutiara Emas Utama (R3), and west lanes, Jalan Mutiara Emas Puteh, (R10), exceeded the capacity and resulted in LOS F. The roundabout’s performance in 2020 was compared to the current year, 2022, with both left-turn lanes achieving a free-flow speed resulting in Level of Service (LOS) B in 2020 and LOS A in 2022. Specifically, the north lane (R2) and east lane (R1) transitioned from LOS B to LOS A in 2020 and 2022, respectively. However, the south lane (R3) and west lane (R1) require capacity and LOS improvements to alleviate traffic conditions. Overall, the project’s success is expected to benefit MBJB by enhancing traffic management in Mount Austin, Johor Bahru.