Coordinated control method to self-equalize bus headways: an analytical method

In an uncontrolled bus line, buses tend to bunch due to the stochastic nature of traffic flow and passenger demand at bus stops. Although bus holding has been shown to effectively prevent bus bunching, this control method often fails when disturbances are large and frequent. A coordinated control method combining two control means (bus holding and stop-skipping) is proposed instead of using only one control means. Bus holding and stop-skipping are integrated with the concept of predictive control. Considering the conciseness and convenience in applications, herein, we propose an analytical method to automatically equalize bus headways in a single line by analyzing bus headways between both its leading and following buses, as well as the number of waiting passengers at the bus stops. Numerical tests conducted in a simplified scenario and random scenario show that the proposed coordinated control method performs better in terms of headway convergence rate and resisting random disturbance than using bus holding only. Moreover, a set of simulation tests based on an actual bus route showed better performance of the proposed coordinated control method with increasing demand in terms of regulating the bus headway, saving the total travel time, and providing reliable service for passengers