California Advanced Clean Fleets: Repeal, Exemptions, and Reporting

The California Advanced Clean Fleets regulation no longer applies to most of the fleets it was originally written for. Following the withdrawal of California’s federal Clean Air Act waiver request in January 2025 and subsequent legal settlements, the California Air Resources Board repealed the rule’s requirements for high-priority fleets, drayage trucks, and federal fleets. The only operators still subject to ACF are state and local government agencies running medium- and heavy-duty vehicles in California, and even those requirements are being amended.

What Was Repealed and Why

Under the federal Clean Air Act, California cannot enforce vehicle emission standards stricter than federal rules without an EPA waiver.¹ CARB submitted its ACF waiver request in November 2023 and withdrew it on January 13, 2025.² No new request has been filed, and EPA’s tracking page lists no pending waiver or authorization for the regulation.³

CARB had already said in October 2024 that it would not enforce drayage or high-priority reporting requirements and registration prohibitions until EPA granted a waiver.⁴ After the waiver was withdrawn and legal settlements were reached with a coalition of states and industry groups, CARB’s Board voted to formally repeal three of the four fleet categories the regulation originally covered:⁵

High-priority fleets, meaning entities with $50 million or more in gross annual revenue or 50 or more vehicles nationwide.
Drayage trucks serving California seaports and intermodal railyards.
Federal fleets operating in California.

If your operation falls only into those categories, you have no current ACF compliance obligation. CARB has also acknowledged it cannot enforce its planned 2036 ban on new internal-combustion truck sales without an EPA waiver, which appears unlikely under the current federal administration.

Who Still Has to Comply

The one surviving piece of ACF applies to state and local government agencies operating medium- and heavy-duty vehicles in California.⁶ No EPA waiver is required for this piece, because California can regulate its own government fleets without federal permission.

Under the original rule, affected government fleets had to ensure at least 50 percent of their annual vehicle purchases were zero-emission beginning January 1, 2024, rising to 100 percent of purchases by January 1, 2027.⁷ CARB’s Board has adopted amendments adding flexibility, but as of April 2026 the modified regulatory text was still in its public comment period and not yet finalized.⁵ Government fleet managers should watch CARB’s rulemaking page for the adopted version.

Model Year Schedule vs. ZEV Milestones

Government fleets have historically chosen between two compliance paths. The Model Year Schedule (the default) requires that every new vehicle added to the fleet be zero-emission, phased in at 50 percent of purchases in 2024 and reaching 100 percent in 2027.⁷ Existing internal-combustion vehicles can stay in service through their useful life, but each replacement must be zero-emission.

The alternative ZEV Milestones Option phases zero-emission vehicles in as a percentage of total fleet size, grouped by vehicle type.⁸ The published milestone tables for Groups 2 and 3 sat in Section 2015.2, which covered the now-repealed high-priority fleets. Government fleets planning to use the milestones path should confirm with CARB which schedule applies under the amended Section 2013 rules once those amendments are finalized.

Extensions and Exemptions

If you’re still covered, the regulation includes several safety valves. Each requires substantial documentation and timely filing.

ZEV Infrastructure Delay

When charging or fueling infrastructure is held up by factors outside your control, a construction delay or site electrification delay extension may be available. You’ll need an executed infrastructure installation contract, a construction permit issued at least one year before the compliance deadline, and documentation from the contractor, utility, or building department explaining the delay.⁹ For electrification delays, you also need the utility application, the utility’s response showing the project will take more than a year, and the executed utility contract.

Vehicle Delivery Delay

If you ordered a zero-emission vehicle in time but the manufacturer can’t deliver, a delivery delay extension is available. You need a written, legally binding purchase agreement signed at least one year before the compliance deadline, specifying the ZEV model, purchase date, and terms for immediate delivery in California.¹⁰ Letters of intent and contingent agreements don’t qualify. If the manufacturer cancels for reasons beyond your control, you have 30 days to submit the cancellation notice to CARB and one year to secure a replacement order.

Daily Usage Exemption

When no available zero-emission vehicle can meet the demonstrated daily mileage or energy needs of the truck being replaced, you can apply for a daily usage exemption.¹¹ You must identify the best available battery-electric vehicle in the same weight class, calculate its range, and submit at least 30 consecutive workdays of telemetry data or usage logs showing the existing vehicle’s daily demands exceed what the electric replacement can deliver.¹² You also have to explain why midday charging at the depot, along the route, or during driver rest breaks would not close the gap. The exemption is not permanent and requires periodic renewal.

Reporting Through TRUCRS

ACF reporting runs through the Truck Regulations Upload, Compliance, and Reporting System, or TRUCRS.¹³ The same portal handles the Truck and Bus Regulation, the Zero-Emission Airport Shuttle Regulation, and the Solid Waste Vehicle Regulation.

For each covered vehicle, you’ll document the vehicle identification number, engine family name from the emission control label, fuel type, and gross vehicle weight rating. Records can be uploaded through prepared data templates or entered manually. Fleets that complete reporting and meet compliance requirements can print a compliance certificate through the system, which may be needed for government contracting or facility access. Keep copies of purchase agreements, registration documents, and any exemption correspondence in case of audit, and check CARB’s reporting guidance before each submission cycle while the amendments are being finalized.

Penalties If You’re Still Covered and Don’t Comply

Violations of CARB regulations are treated as misdemeanors under the California Health and Safety Code, carrying fines of up to $5,000 per violation, up to six months in county jail, or both.¹⁴ Each day a violation continues counts as a separate offense. Enhanced penalties apply for knowing or willful violations under related code sections. As a practical matter, CARB’s enforcement focus is now limited to government fleets, since those are the only entities with active ACF obligations.

Incentives If You Transition Anyway

Even with most of ACF off the books, operators choosing to electrify can still tap funding.

California’s Hybrid and Zero-Emission Truck and Bus Voucher Incentive Project (HVIP) provides point-of-sale vouchers that reduce the purchase price of qualifying zero-emission trucks and buses. As of late 2025, incentive ranges by vehicle type ran from $15,000 to $120,000 for straight trucks, $15,000 to $150,000 for shuttle buses, and $60,000 to $216,000 for school buses.¹⁵ Availability depends on remaining funding, so check the HVIP portal before placing an order.

On the federal side, the Commercial Clean Vehicle Credit under IRC Section 45W, which offered up to $40,000 for heavy-duty zero-emission vehicles, expired for vehicles acquired after September 30, 2025.¹⁶ No federal tax credit currently replaces it for commercial zero-emission vehicles purchased in 2026. EPA’s Clean Heavy-Duty Vehicles Grant Program has awarded approximately $595 million across school bus and vocational vehicle sub-programs, though future grant rounds had not been announced at the time of writing.¹⁷

1
Office of the Law Revision Counsel. 42 U.S. Code 7543 – State Standards
2
US EPA. Withdrawal of California’s Request for a Waiver for Advanced Clean Fleets Regulation
3
US EPA. Vehicle Emissions California Waivers and Authorizations
4
California Air Resources Board. Advanced Clean Fleets Enforcement Notice
5
California Air Resources Board. Public Availability of Modified Text and Additional Information for Advanced Clean Fleets Regulation
6
Cornell Law Institute. California Code of Regulations Title 13, 2013 – State and Local Government Fleet Applicability, Definitions, and General Requirements
7
California Air Resources Board. Advanced Clean Fleets Regulation – State and Local Government Agency Fleet Requirements Overview
8
California Air Resources Board. Advanced Clean Fleets Regulation – ZEV Milestones Option
9
California Air Resources Board. ZEV Infrastructure Delay Extension Checklist
10
California Air Resources Board. Advanced Clean Fleets Regulation – Vehicle Delivery Delay Extension
11
California Air Resources Board. Advanced Clean Fleets Regulation – Daily Usage Exemption
12
Cornell Law Institute. California Code of Regulations Title 13, 2015.3 – High Priority and Federal Fleets Exemptions and Extensions
13
California Air Resources Board. TRUCRS Reporting Information
14
California Legislative Information. California Health and Safety Code 42400
15
California HVIP. California HVIP – Clean Truck and Bus Voucher Incentive Project
16
Internal Revenue Service. Commercial Clean Vehicle Credit
17
US EPA. Clean Heavy-Duty Vehicles Grant Program Awards