Optimal operating strategy of short turning lines for the battery electric bus system

Abstract

Operating short turning line is an efficient strategy to satisfy the unevenly distributed demand during peak periods while reducing operational cost. However, for the battery electric bus (BEB) system, the application of the strategy is challenging due to the disadvantages of BEBs, such as limited driving mileage and long charging time. Improper vehicle configuration and charging scheduling may dramatically increase the operational cost and cut the benefits of these strategies. In this work, we propose a general framework to design an effective short turning strategy for the BEB system at a tactical planning level. First, the trade-off relationship between the battery capacity and the average trip time is identified by modeling the BEBs operations. Second, a microeconomic model is formulated to jointly optimize the frequencies and charging schedules of the whole bus line and the short turning line, to effectively minimize passengers’ waiting time and operational cost. Finally, numerical experiments have been carried out for an illustrative linear line to demonstrate the potential benefits of the sub-line operating strategy compared with the normal operation.