Operational Analysis of U-Turning Vehicles -A Case Study in Trivandrum

Abstract

Median openings are provided in multilane divided roads to enable U-turns. The behaviour of U-turning vehicles at two median U-turns in Trivandrum is studied in this paper. U-turns at median openings are complex because the vehicle is required to take 180° turn in a smaller width of road. Delay time, merging time, critical gap and conflicting flow rate were some of the parameters that were analysed at uncontrolled median openings. The delay and merging time of vehicles on the U-turns considered were studied using INAFOGA (Influence Area for Gap Acceptance) method. The gap acceptance behaviour and waiting time of the driver are determined by the critical gap. Critical gap was estimated using clearance behaviour of vehicles along with gap acceptance data. The variation of delay time, merging time and accepted gap with conflicting flow rate is plotted using microscopic analysis. The dependence of delay time, merging time, and critical gap of each classified vehicle types was also analysed.