PROJECT TITLE :

Comparison of delay estimation models for signalised intersections using field observations in Shanghai

ABSTRACT:

Vehicular management delay is vital in evaluating the level of service and planning or adjusting the management schemes at signalised intersections. Though management delay may be obtained directly or indirectly nowadays for vehicles with global positioning system (GPS) or at locations with designated sensor types and configurations, such data are still not widely available. The analytical and empirical procedures for management delay estimation are still vital, particularly in developing countries. However, very few studies explored the effectiveness of existing management delay estimation ways. This study intends to address this issue by comparing the delays estimated by four commonly adopted models using field knowledge observed from 3 signalised intersections in Shanghai. Specifically, the study compares the delay estimates from deterministic queuing model, Webster model, highway capability manual (HCM) 200zero model, and Shanghai adjusted model. The results indicate that HCM 200zero model and Shanghai adjusted model perform equally and satisfactorily underneath varied v/c ratios while deterministic queuing model has higher performance when the v/c ratio is extremely high, but Webster model is largely inadequate at coordinated signalised intersections. Meanwhile, signal progression, initial queue, proportion of vehicles arriving on inexperienced are found as main influential factors to the precision of models based mostly on data analysis.