Modeling Bus Bunching and Anti-bunching Control Accounting for Signal Control and Passenger Swapping Behavior

Abstract

The conventional bus propagation modeling process has two main shortcomings: bus bunching and extra energy consumption caused by idling at signalized intersections and unexpected speed variation along the route. To overcome these problems simultaneously, an extended bus propagation model and anti-bunching control are proposed in this paper. To extend the time-based bus propagation model, the authors used a finite state machine and an intelligent driver model to establish a spatial-temporal based bus propagation model accounting for dynamic bus motion and passenger swapping behavior between bunched buses. To mitigate bus bunching and improve fuel economy in a connected environment, an anticipated average speed plan was used to improve headway regularity and reduce the chance of encountering a red signal. Then, predictive control accounting for state and control constraints was used to generate a smooth trajectory for connected buses to follow the commands given by anticipated average speed planning. This ensured that connected buses traversed signalized intersections and approached downstream stops efficiently. Simulations show that the proposed model can imitate passenger swapping behavior when bus bunching occurs, and the anti-bunching control can mitigate bus bunching and guide connected buses to traverse signalized intersections and reach downstream stops with less delay.