Electric vehicle type selection for single-line transit fleet replacement

Abstract

Fleet replacement is an important decision-making activity in public transit planning and operations. Recently, with the goal of reducing carbon dioxide emissions and achieving carbon neutrality, diesel buses are being replaced with new electric buses (EBs) in many cities around the world. The study proposes a methodology to analyze and compare the life-cycle cost and passenger waiting time of multi-type EBs, so as to assist transit agencies in determining the optimum EB type to replace existing diesel buses. The proposed methodology is applied to a real-life case study of a bus line in Dandong, China. The case study includes six types of EBs categorized by their charging technologies and passenger capacities, including three slow-charging EBs with capacities of 40, 60, and 76 passengers, as well as three fast-charging EBs with capacities of 50, 65, and 75 passengers. The results show that no matter which charging technology is considered, the life-cycle cost of large-size EBs is the lowest. From the perspective of passengers, small-size EBs resulting in shorter waiting time are more favorable. When passenger demands on all route segments change with the same rate, the total passenger waiting time for each vehicle type will not change. But, with the increase of passenger demand, the average passenger waiting time decreases for all vehicle types. The results also indicate that the bus line length does not have a significant impact on EB vehicle selection. In addition, the phase-out of the vehicle purchase subsidy policy will have no impact on EB type selection due to the current low-level purchase subsides.