CARB approves amendments to clean truck standards to provide flexibility

The California Air Resources Board recently approved amendments to the state’s Advanced Clean Truck and Zero-Emission Powertrain Certification standards to maintain the emissions benefits while providing manufacturers additional flexibility. The board said its actions also support commitments made in the Clean Truck Partnership, an agreement with the nation’s major truck manufacturers to reduce emissions from the trucking industry.

“California’s commitment to cleaner trucks has created an ecosystem of programs and incentives that will continue to drive progress despite the federal administration’s unlawful actions challenging our state’s efforts to reduce emissions and deploy to clean transportation technologies,” said CARB Chair Liane Randolph. “The amendments approved today provide manufacturers with flexibility, and we look forward to continued collaboration with manufacturers in efforts to reduce emissions, protect public health, and ensure global competitiveness as the rest of the world shifts to zero-emission technologies.”

The amendments, which the board said brings no significant cost or emissions impact, were developed in response to stakeholder comments and include:

• Adding a “pooling” option for manufacturers to transfer surplus zero-emission vehicle and near-zero emission vehicle credits generated between states that adopted the ACT regulation.
• Permitting manufacturers to offset a portion of deficits generated in the Class 7-8 tractor group with Class 2b-3 or Class 4-8 group ZEV credits for each model year, allowing manufacturers more flexibility and to account for fluctuations in ZEV and NZEV sales across states and vehicle classes.
• Adjusting the minimum all-electric range requirement for NZEV in later years.
• Providing manufacturers increased flexibility on the order in which they retire credits.
• Modifying the communication protocols of the ZEV connector criteria for certifying zero-emission powertrains.

See also: Trump revokes CARB’s waivers, but it’s not the last word

How we got here

The ACT regulation was adopted by the board in 2020. It is part of a strategy to reduce harmful emissions from medium- and heavy-duty vehicles by increasing the production and sale of ZEVs.

In 2023, CARB and truck and engine manufacturers announced the Clean Truck Partnership to advance the development of ZEVs for the commercial trucking industry. Through the partnership, truck manufacturers committed to meeting CARB’s regulations in the state regardless of CARB’s overall authority to implement those regulations.

On June 12, 2025, President Trump signed resolutions purporting to overturn three of the U.S EPA’s decisions to grant California waivers, including its Advanced Clean Cars II, Advanced Clean Trucks, and Heavy-Duty Engine and Vehicle Omnibus regulations. These resolutions are currently the subject of litigation and are separate from the latest amendments.

Following the president’s action, CARB released guidance for manufacturers subject to the regulations. The advisory explained that CARB would continue accepting and processing certification applications for 2026 models to ensure continuity and enable lawful vehicle sales in California.

In response to federal efforts to revoke California’s clean air waivers, Governor Gavin Newsom signed an executive order on June 12, 2025. The order directs state agencies to assess additional actions to spur light-, medium-, and heavy-duty zero-emission vehicle adoption in California, and to deliver formal recommendations for additional actions to the governor in August.