Revisiting Delay Model of Signalized Intersections

Vehicle delays at signalized intersections are an important factor in evaluating the operation efficiency and the level of service at intersections. At present in China, some research institutes and researchers are working on delay models from theoretical studies. They often directly use models from foreign countries without calibration or modifications, which often results in significant discrepancies between the theory and reality. The objective of this paper is to establish a delay model that is adequate for the actual traffic conditions in Beijing. The model can provide a better ground for planning and design of intersections. For this reason a total of forty signalized intersections in Beijing were selected to conduct the investigation, together with the analysis on vehicle delay and queue length. Based on the regression analysis with field data, a planning-based delay model at signalized intersections is proposed. The result from this study shows that this model greatly simplifies the procedure of the theoretical delay model. It also avoids cumbersome and complicated calculations of the traditional delay model. In conclusion, the model is an effective evaluation tool and the results are in line with the actual traffic situations in Beijing.