Understanding California’s Advanced Clean Fleet Regulation

The Advanced Clean Fleets (ACF) regulation aims to phase out internal combustion engine medium- and heavy-duty trucks in California to achieve a zero-emissions transport system by 2045. The regulation mandates ZEV adoption for high-priority, drayage, and public fleets through various schedules and milestones, with CARB providing extensions for infrastructure, electrical, and delivery delays. The regulation is estimated to reduce CO2 emissions by nearly 25 million metric tons between 2024 and 2041.

• The Advanced Clean Fleets (ACF) regulation targets the phase-out of medium- and heavy-duty (MDHD) internal combustion engine trucks to support California's goal of a zero-emissions transport system by 2045.
• Compliance requirements for ACF are divided among three fleet categories: high-priority fleets (over 50 trucks or >$50 million annual revenue), drayage truck fleets (operating at ports or intermodal rail yards), and public fleets (state and local government agencies).
• High-priority fleets can comply via a ZEV model year schedule, requiring all new purchases to be ZEVs starting January 2024, or through ZEV milestones based on vehicle size and model year percentage targets.
• Drayage fleets must purchase only ZEVs starting in 2024 and ensure all fleet trucks are ZEVs by 2035. Public fleets must ensure 50 percent of new purchases are ZEVs from 2024 to 2026, with 100 percent from 2027 onward.
• The California Air Resources Board (CARB) allows extensions for ZEV adoption due to infrastructure construction, utility electrical upgrades (sunsetting in 2030), vehicle delivery delays, or if available ZEVs do not meet duty-cycle requirements.
• CARB estimates that the ACF regulation will reduce emissions by nearly 25 million metric tons of CO2 between 2024 and 2041.

APA

RMI (2023). Understanding California’s Advanced Clean Fleet Regulation. https://rmi.org/resources/understanding-californias-advanced-clean-fleet-regulation/

Chicago

RMI. Understanding California’s Advanced Clean Fleet Regulation. 2023. https://rmi.org/resources/understanding-californias-advanced-clean-fleet-regulation/.

Wikipedia

{{cite report |author=RMI |title=Understanding California’s Advanced Clean Fleet Regulation |date=3 July 2023 |url=https://rmi.org/resources/understanding-californias-advanced-clean-fleet-regulation/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2023understanding, author = {{RMI}}, title = {{Understanding California’s Advanced Clean Fleet Regulation}}, institution = {RMI}, year = {2023}, month = jul, url = {https://rmi.org/resources/understanding-californias-advanced-clean-fleet-regulation/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }