Calibration of Performance of Roundabouts Based on Gap Acceptance Parameters Using Simulation for Indian Scenario

Abstract

Indian traffic is characterized by wide range of variations and heterogeneous composition. This makes the driver behaviour a prominent feature for developing traffic models and simulations. In this study, detailed analysis is carried out to simulate a traffic model for roundabouts using the entry and the circulating flow values to calculate the gap acceptance parameters like critical gap and follow-up time. To measure the critical gap of entry of roundabouts incorporating distribution of headways, statistical techniques like equilibrium of probabilities and cumulative probability density function are used. The equilibrium of probabilities method was found to overcome few assumptions relating to homogeneity used by several methods. The simulation was carried out using VISSIM software taking the vehicle dimensions and flow values as input parameters. Deceleration and minimum headway were used as calibrating parameters to simulate the model. The values of critical gap and follow-up headway showed less variation with those obtained using equilibrium of probabilities method.