Effects of bunching at stops on bus dwell time

Dwell time is an important factor affecting the service capacity of bus route, but the limited capacity of bus stops may lead to the bunching problem which will cause longer dwell time for serving passengers, especially for the corridor with several collinear bus routes. In this paper, two groups of regression models for dwell time estimation were proposed to verify and calibrate the effects of bunching and different passenger demand variables on dwell time. With the observed data, the regression results show that the bunching does have a significant effect on dwell time and contributes an additional 4.22 to 6.23 seconds to the dwell time of buses bunched with their preceding one. Besides, the dwell time is found to be most correlated to the sum of boarding and alighting passengers for the non-bunched trips and the number of boarding passengers for the bunched trips.