Effect of vehicle composition on saturation flow at signalised intersections in mixed traffic conditions

Abstract

Vehicular traffic in most of the developing countries is a mixed traffic flow condition with non-lane-based behaviour in urban roads. Vehicles with different static and dynamic characteristics share a common lane. Signalised intersections provide sequential movements of vehicular traffic from one leg to another leg. Saturation flow is an important parameter for the measurement of the level of service at signalised intersections. The various equations, developed for the estimation of saturation flow, for a mixed traffic flow condition do not consider the non-lane-based traffic conditions. There is a need to establish a model to estimate the saturation flow of a signalised intersection for a non-lane-based vehicular movement in mixed traffic flow conditions. This research work presents the findings of the analysis of saturation flow conducted at signalised intersections in three different cities, Warangal, Raipur, and Calicut, in India. Flow rate and traffic volume data are collected using a video graphic technique and the Transportation Research Record Laboratory direct vehicle count method is used to estimate saturation flow. The developed model shows good predictability in comparison with observed data and can be used to estimate saturation flow in non-lane-based traffic conditions.