Passenger boarding behavior assignment approach to mitigate unreliable operation of bus lines

Headway fluctuations, including bus bunching and big gaps, are frequent challenges in public transit operations. Although effective control strategies have been developed to address these issues, practical implementation often encounters significant limitations in real-world settings. In this study, passenger boarding behavior is regulated to adjust waiting times at stops, thereby mitigating the bunching effect. To support this approach, operational unreliability is classified into eight distinct scenarios, with threshold values defined to differentiate among them. A passenger boarding behavior assignment model is proposed, incorporating three strategies: separate limited boarding, coordinated limited boarding and extended queue swapping. These strategies are designed to respond to the previously defined unreliability scenarios. The proposed approach is evaluated in a simulated environment under various operational conditions. Results demonstrate that the assignment of passenger boarding behavior improves the stability and service quality of bus operations. Specifically, the coordinated limited boarding strategy compensates for the limitations of separate boarding by distributing high passenger volumes more effectively with fewer boarding restrictions. The extended queue swapping strategy reduces bus bunching, increases the utilization of low-occupancy vehicles, and minimizes capacity waste.