Operational Feasibility of Battery Swapping in U.S. Transit: A Case Study of King County Metro

Battery swapping technology has emerged as a promising alternative to conventional plug-in charging for electric bus fleets, offering rapid turnaround times and improved vehicle availability. This paper investigates whether battery swapping can be integrated into U.S. public transit bus operations without disrupting existing timetables. A Seattle based public transit agency- King County Metro is taken as a case study in this paper. Using General Transit Feed Specification data from King County Metro, a MATLAB model was built that reconstructs blocks and layovers, extracts dwell-time opportunities, and performs block distance and block time analyses to understand operational rhythms. A mathematical energy model was developed that maps route mileage, efficiency, and layover availability to swap decisions, using a look-ahead rule that defers exchanges whenever the next feasible layover can still be reached while respecting a minimum state-of-charge. The workflow estimates how many swaps each block would require over a service day, the effective driving range a pack can deliver between exchanges, and the spatial clustering of recurring layovers suitable for station placement. Results indicate that swap windows naturally emerge from scheduled layovers, enabling a swapping system to be layered onto current service patterns, sized by corridor demand, and planned within existing operational constraints. The approach offers a practical template for agencies to assess technical and operational feasibility and to plan right-sized battery-swapping infrastructure.