Evaluation of real-time holding strategies for improved bus service reliability

Service reliability is one of the main measures of performance determining transit system level of service. Holding control strategies are a common transit operations practice aimed to reduce transit service unreliability by setting criteria for departure from time point stops. In order to adequately analyze the sources of uncertainty involved with transit performance, it is essential to model dynamically the interactions between traffic conditions, passenger demand and transit operations. BusMezzo, a transit simulation model has been developed on a platform of a mesoscopic traffic simulation model, which enables the representation of large-scale transit systems. The model implements several real-time holding strategies. It is used to evaluate the application of these strategies in a real-world high-demand bus line in the Tel Aviv metropolitan area, under various scenarios. An analysis of the results suggests that a holding strategy based on the mean headway from the preceding bus and the next bus, restricted by a maximum allowable holding time, is especially efficient.