Estimating capacity for eight-lane divided urban expressway under mixed-traffic conditions using computer simulation

Abstract

Expressways in India are vastly different from other roads of the country based on roadway and traffic conditions and additionally, there is no perfect strict lane discipline. Nevertheless, there is not much research literature available specific to these categories of roads in India. The knowledge of roadway capacity is an important basic input required for planning, design, analysis and operation of roadway systems. Hence, this work aims to model traffic flow on Indian urban expressways with specific reference to Delhi–Gurgaon expressway and estimate its capacity using the micro-simulation model, VISSIM. Field data collected on traffic flow characteristics on expressways are used in calibration and validation of the simulation model. The validated simulation model is then used to estimate passenger car unit (PCU) values for different vehicle types and derive capacity value. It was found that the PCU value for each of the vehicle categories decreases with increase in vehicular flow under uncongested regime. It was also found that the PCU value for heavy and larger vehicle types are higher under congested regime as compared to their respective PCU values near capacity. The capacity of a eight-lane divided urban expressway in level terrain with 14.0 m wide road space is found to be about 9700 PCU/h, for one direction of traffic flow.