Impact of dedicated mini roundabout on the capacity and level of services of the unsignalized intersection

This paper is aiming at investigating the impact of dedicated mini-roundabout on the capacity and level of services at a four-legged unsignalized intersection. The assessment was carried out based on two scenarios namely before the installation mini-roundabout (existing) and after installation (improvement). Datasets were collected at Ujung Stasiun KA unsignalized intersection, which is in the center of Bireuen City, Aceh province of Indonesia. A video-cameras are installed to observed traffic patterns including hourly volume, movement trajectories, and vehicle composition during three days on a morning, afternoon, and evening peak hour traffic. The Indonesian highway capacity manual (IHCM, 1997) is used to evaluate the capacity and level of service in existing conditions while the simulation approach using VISSIM is then performed to assess the scenario of virtual implementation dedicated mini roundabout. The result of analysis demonstrates that the capacity of unsignalized slightly increases by 5% while the delay and level of service are significantly reduced to 42% (31.02 sec to 18 sec), and improved from E to C, for delay and LOS, respectively. It can be concluded that the improvement of the existing condition by implemented a dedicated mini roundabout could improve the capacity and LOS in the study area.