Saturation flow estimation at signalized intersections under mixed traffic conditions

Abstract

Signalized intersections are one of the major influencing factors for designing an efficient urban road network. Hence, it is necessary to design an efficient intersection. Saturation flow is crucial for designing the signal cycle and the corresponding green phase at an intersection. It is the most fundamental parameter governing capacity of a signalized intersection. But estimation of saturation flow based on field measurements is quite tedious and time-consuming. This difficulty is further aggravated for researchers in developing countries where the traffic condition is highly heterogeneous with almost no lane discipline. In order to address this issue, this paper presents a formula for computing the saturation flow under mixed traffic conditions. The model is presented for the computation of total saturation flow based on road width, the composition of traffic and percentage of right turning vehicles in the approach. Unlike conventional methods, the proposed formula represents saturation flow in vehicles/hr of green/lane to circumvent the tedious job of computing passenger car unit for different types of vehicle at signal controlled intersections.