Computation of Time Delay at Signalized Intersection

The objective of this paper is to calculate the average time delay caused to vehicles at signalized intersections, which is an important criterion in the evaluation of performance of signalized intersections. Various models have been developed to estimate delay to traffic at signalized intersections, and all these models are based on homogeneous traffic conditions. In this study an attempt has been made to develop a delay model in order to estimate the delay caused to vehicles given the basic data, which is easily measurable at signalized intersections under heterogeneous traffic conditions. The Highway Capacity Manual (HCM) method modeling technique has been adopted to estimate the saturation flow and the delay caused to traffic at signalized intersections under heterogeneous traffic conditions. The interactions between the different types of vehicles are incorporated in the modified Webster model by considering the intercorrelation between different vehicle groups. The input data required for these models and the data required to validate the calculated values were collected by conducting extensive traffic surveys at Balnagar signalized intersections in the city of Hyderabad, India. Computational results showed that the delay estimated by surveyed procedure matches with the delay calculated by Webster and HCM procedure at 10 to 15% variation.