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Regulatory Whiplash: CARB Set to Repeal Key Portions of ACF Rule—What It Means for Fleets

By: Suzanne Seivright-Sutherland

In a major regulatory shift, California Air Resources Board (CARB) announced plans to repeal the High Priority Fleets and Drayage Truck components of the Advanced Clean Fleets (ACF) rule. This decision stems from a legal settlement with a coalition of 17 states and key trucking industry organizations that challenged the rule's legality, particularly its extraterritorial implications and federal preemption issues. Under the terms of the settlement, CARB must begin the formal repeal process by October 31, 2025, and finalize it by August 31, 2026. Until then, CARB has agreed to suspend enforcement of these specific provisions.

This development marks a substantial departure from CARB's previous trajectory and offers immediate regulatory relief for many private fleets. The ACF rule, as originally structured, imposed aggressive zero-emission vehicle (ZEV) purchasing requirements, compliance deadlines, and reporting mandates. These requirements posed significant operational and financial challenges, particularly for fleets with long equipment replacement cycles and limited access to ZEV infrastructure. The suspension removes short-term compliance pressure, giving fleet managers breathing room to pause, reevaluate capital planning, and reallocate resources as needed.

However, this pause does not eliminate the long-term trajectory toward zero-emission transition. CARB has made it clear that it retains the authority to pursue future ZEV fleet regulations, potentially without the need for a federal waiver, so long as new rules address the legal vulnerabilities highlighted by the recent challenge. This means a retooled regulatory framework could be reintroduced in the near future, particularly if legal and political conditions shift. Moreover, the public fleet provisions of ACF remain in effect, and CARB is likely to use public sector implementation as both a proving ground and a guide for future private sector mandates.

Now is also a critical time for fleet operators to reflect on the broader policy landscape. Depending on the outcome of upcoming federal elections, national regulatory direction may either reinforce or diverge from California's clean air policies. A future administration aligned with California's environmental goals could restore momentum for aggressive decarbonization standards, whether through federal initiatives or renewed state-federal cooperation.

What should fleets do now?

Every fleet is unique in its operations, risk profile, and long-term planning. We strongly encourage members to consult their legal, regulatory, and fleet advisors to reassess compliance strategies, investment horizons, and technology adoption plans. While immediate deadlines have been lifted, regulatory volatility remains a reality, and preparation will offer a competitive edge.

CalCIMA will continue to monitor developments closely and keep members informed as CARB moves through the repeal process and contemplates future actions.

Stay engaged. For ongoing updates, subscribe to CARB's ZEVfleet email list via: GovDelivery – ZEVfleet