Optimal design of electric bus short turning and interlining strategy

Short turning and interlining lines allow transit agency to circulate a small number of vehicles between high demanded segments and are efficient strategies for addressing the problem of vehicle underutilization in peak period. With the electrification of urban transit system, the application of these strategies is faced with new challenges due to the limited battery capacity and long charging time of battery electric buses. Without rigorous charging scheduling, the short turning and interlining strategies may not perform as intended. This study presents a comprehensive framework to deal with the joint problem of short turning and interlining line planning, frequency setting and charging scheduling. We formulate the problem as a mixed-integer nonlinear programming model and propose an exact solution approach. Numerical experiments have been carried out for the Beijing Third Ring bus network; the potential benefits of the strategy-based operation are demonstrated by compared with the optimized normal operation.