Modelling the effect of buses on signalized intersection capacity

Passenger car equivalents are used to represent the varying effects of mixed vehicle types such as buses on saturation flows by converting a traffic stream comprising of various vehicle types into an equivalent traffic stream comprising entirely of passenger cars (PCE). However Buses do not necessarily have the same effects as trucks in urban facilities. Buses stopping to load and unload passengers are expected to produce longer delays. According to Highway Capacity Manual (HCM), if there is a bus stop which is close to a signalized intersection, a correction factor is used for calculating the capacity of this signalized intersection.This study is focused on the operational non-operational performance of buses and quantifies their impacts in traffic streams, particularly at signalized intersections in urban areas. The methodologies presented in this study are based on headway ratio (HR) for evaluating PCE and bus blockage factor for signalized intersections.