Optimal Mixed Fleet Bus Scheduling: Bridging Electrical and Conventional Solutions

Several Northern Virginia public transit agencies are transitioning their diesel-powered bus fleets to battery electric buses (BEBs). While BEBs provide benefits in terms of environmental sustainability, operational cost, and reduction in noise pollution, reorganizing a transit feet and its support infrastructure to incorporate electric buses poses several challenges. Chief among these is an impact to range and refuelling capabilities in comparison to conventional diesel buses, where BEBS may need to recharge multiple times in a day in contrast a diesel bus’ refuelling schedule of three to four days depending on route. Length of an assigned transit block, ability to access a charger during the day, and the total charging capacity must be considered, One local transit agency, the DASH Alexandria Transit Company, has begun this transition and has accessible real-world data on the existing implementation of 14 BEBs operational in Alexandria as of March 2025. In order to support this transition as the number of operational BEBs increases, an integer programming model has been developed support DASH's goal of achieving a zero-emissions fleet by 2038. The model accounts for current planning and scheduling constants of the agency. including existing public facing trip schedules, bus deployment duration a limited by available charge, and existing charging infrastructure, The integer program minimizes the total cost of feet operations by prioritizing available electric buses for black assignments, The model is intended as tool to support real-world decision-making regarding BEB assignment and potential infrastructure expansion