DELAY ESTIMATION AT SIGNALIZED INTERSECTION

Abstract

Delay is an important parameter used in the optimization of traffic signal timings and estimation of level of service of signalized intersection approach. However delay is also a parameter that is difficult to measure, and which provoked many researchers to develop analytical models for delay estimation. This study ighlights the consistency among these estimates. Specifically the study compares delay estimates from a deterministic queuing model, the steady-state Webster model, the queue based models defned in the 1981 Australia capacity Guide, the 1995 Canadian Capacity Guide for Signalized intersecions, and the 1985, 1994, 1997 and 2000 versions of the Highway Capacity Manual (HCM) model. Signalized intersection approach controlled in fixed -ime and operated in a range of conditions extending from under-saturation to highly saturated is used for this study. The results of the analysis indicate that all delay models produce similar results for signalized intersection with low traffic demand, but the increasing differences occur as the traffic demand approaches saturation.