Suggested Citation:
Lipman, Timothy E. (2026)

Brief: Decarbonizing Heavy-Duty Transportation Modes with Electricity, Biofuels, and Hydrogen

. Institute of Transportation Studies, University of California, Davis, Brief UCD-ITS-RR-26-21

Abstract:

Heavy-duty transportation modes including trucks, buses, and seaport and airport equipment are relatively hard to decarbonize because of their demanding performance requirements and other factors. The California Scoping Plan for Achieving Carbon Neutrality calls for carbon-neutral transportation across all modes by 2045, with different sectors reaching 100% zero-emission vehicle (ZEV) sales by earlier dates, depending on the type of vehicle (see EO N-79-20). For public transit buses, the state’s Innovative Clean Transit rule requires both large and small transit agencies to cease purchasing combustion engine buses in 2029 in favor of zero-emission (ZE) technologies, with a phased approach that has already commenced. However, for trucks, achieving the transition to ZEVs is more problematic as the state’s Advanced Clean Fleets rule is only applicable to government fleets at present, and the Clean Truck Partnership memorandum of understanding with truck manufacturers is effectively on hold pending legal actions.