Coordinated Transit Signal Priority and Vehicle Guidance for Automated Buses

Automated buses are attracting increasing attention for enhancing the efficiency of existing bus systems. However, operational challenges persist for two-way automated buses on arterial roads, particularly in ensuring their on-time performance. This study proposes a center-based cooperative control between transit signal priority and vehicle guidance. The proposed model establishes an interactive structure between transit management and signal control systems within a traffic management center, which simultaneously optimizes traffic signal operation and bus trajectories. The control generates planned bus schedules and traffic signal timing plans through fixed-time strategies. When buses deviate from their schedules, the proposed model supports schedule recovery through reactive priority and vehicle guidance, including departure control at bus stations and adaptive speed adjustments. A numerical simulation was conducted in Sejong, Korea, under various boarding and alighting times and headway conditions. The results reveal significant improvements in bus route schedule deviations by 51.8-57.3% compared to active priority and speed guidance with active priority. The proposed approach can enhance public transit reliability and urban traffic flow by effectively integrating automated buses with traffic signal operation.