MICROSIMULATION ANALYSIS OF THE IMPACT OF U-TURN MEDIAN OPENING DESIGN AND CONFLICT FLOW ON U-TURN CAPACITY

• Main Author: Rizki Muharam, Fauzan
• Format: Theses
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/84681
• Institution: Institut Teknologi Bandung

The u-turn movement at a median opening is a highly complex case compared with turning movements at intersections. Several studies have addressed the phenomenon of u-turn movements to assess the performance of median openings based on capacity using analytical methods by Harder (1968) and Kyte (1992). However, these analytical methods have limitations, as they applied only to one type of facility and cannot be used for operational performance evaluation. Additionally, existing research has not examined the effect of variations in median opening shapes on the traffic performance of median openings. Microscopic simulation models using PTV VISSIM were used to model cases of different median u-turn openings at the Ir. H. Juanda and Cikapayang review locations to further study the impact of opening shapes on traffic performance in u-turn cases. Calibration was performed on driver behavior parameters and priority rules, which were then validated with field data to visually and statistically match with field conditions. The output of the reviewed model includes merging time and headway time, both parameters are used to calculate u-turn capacity with the Kyte method. The modeling results indicate that the error in model-field capacity is smaller compared to the analytical-field capacity, meaning the model accurately represents field conditions. The microscopic simulation model was then developed with scenarios involving changes in conflict flow and u-turn shapes. From this development, it was found that as the conflict flow increases, the u-turn capacity decreases. The sequence of changes in u-turn shapes under existing traffic conditions based on capacity values is as follows: channelization, roundabout, conventional (existing), and indirect right u-turn. Furthermore, the relationship between changes in conflict flow and shape shows that the most effective shape for conflict flows <2800 vehicles/hour is channelization, while for conflict flows >2800 vehicles/hour, the conventional (existing) shape has better capacity values.