This emphasis provides State and Local Governments with adequate time to ensure compliance and recognizes the constraints public agencies encounter when procuring vehicles. This compliance assistance will focus on meeting the reporting obligations as agencies work to meet their fleet obligations.

CARB intends to emphasize education and outreach for the first reporting cycles of implementation of ACF. During this time, CARB will focus its efforts on implementing the reporting requirements and improved flexibility provisions and exemptions. CARB will evaluate how effective the flexibilities are in addressing each agency’s implementation concerns. CARB will work with agencies on a case-by-case basis to address their issues. CARB will apply lessons learned from agencies to evaluate future regulatory modifications that would help support agencies in their planning.

The proposed amended ACF regulation expands flexibility for all State and local government agencies while ensuring continued progress toward reducing and eliminating harmful motor vehicle emissions. Of particular note, the proposed amendments make clear that a public agency’s fleet includes vehicles it directly owns as well as vehicles it rents, leases, or contracts to operate on its behalf. The ACF regulation, as proposed to be amended, does not apply to private fleets. If a public agency has questions about how to report or utilize any of the flexibilities for the vehicles that it owns, rents, leases, or operates under contract, please contact CARB staff at zevfleet@arb.ca.gov (mailto:zevfleet@arb.ca.gov).

Purpose of the Advanced Clean Fleets Amendments 

The proposed amendments are designed to: 

• Improve compliance flexibility for public fleets
• Repeal the High Priority Fleets and Drayage portions to provide greater regulatory certainty for private fleets
• Clarify responsibilities related to vehicles under contract

Key Updates in the Second 15-Day Modifications 

CARB issued the second 15-day changes to the ACF regulation to address confusion regarding vehicles under contract to State and local government agencies. The modifications clarify the following existing requirements as intended in the initial ACF amendment language released on July 29, 2025: 

• Public agencies must report vehicles under contract in their fleets when determining compliance with the ACF regulation. 
• Private fleets are not subject to the ACF State and local government regulations. 
• The regulation applies to public services performed by a State and local government agency, including functions carried out through contractual arrangements.

Reporting Guidance for State and Local Government Agencies 

• A public agency fleet must report vehicles it directly owns, rents, leases, or contracts to operate on its behalf, per section 2013.3 of the regulation.
  • State and local government agencies must report any covered vehicle added to its California Fleet through a binding agreement with a third party.
  • Vehicles that are renewed through existing leases or service contracts do not need to be counted as added vehicles.
• State and local government agencies can subdivide their fleet into different compliance pathways. For example, contracted vehicles can be put on the zero emission vehicle (ZEV) Milestone Option compliance pathway (https://ww2.arb.ca.gov/resources/fact-sheets/advanced-clean-fleets-regulation-zev-milestones-option) and vehicles they directly own can be put on the ZEV Purchase Schedule pathway if they choose.
• State and local government agencies have full access to exemptions and extensions for all vehicles in their fleet; including those rented, leased or under contract.   
• State and local government entities have considerable flexibility in deciding how to obtain ZEVs to remain compliant with ACF, and may do so through vehicles they own, rent, lease, contract or combinations in between to meet their compliance obligations.