SACRAMENTO – The California Air Resources Board (CARB) today approved amendments to the state’s Advanced Clean Truck (https://ww2.arb.ca.gov/our-work/programs/advanced-clean-trucks) (ACT) and Zero-Emission Powertrain (ZEP) Certification (https://ww2.arb.ca.gov/our-work/programs/zero-emission-powertrain-certification) standards to maintain the emissions benefits while providing manufacturers additional flexibility. The Board’s actions also support commitments made in the Clean Truck Partnership (https://ww2.arb.ca.gov/clean-truck-partnership-home), an agreement with the nation’s leading 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 constitute minor changes with 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 (ZEV) and near-zero emission vehicle (NZEV) 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. 

How we got here 

The ACT regulation was adopted (https://ww2.arb.ca.gov/news/california-takes-bold-step-reduce-truck-pollution) by the Board in 2020. It is part of a comprehensive 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 (https://ww2.arb.ca.gov/news/carb-and-truck-and-engine-manufacturers-announce-unprecedented-partnership-meet-clean-air) 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 (https://ww2.arb.ca.gov/news/carb-chair-liane-randolph-responds-president-trumps-approval-illegal-resolutions-revoke) unconstitutional and illegal resolutions purporting to overturn three of 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 (https://www.gov.ca.gov/2025/06/12/assault-on-california-continues-governor-newsom-sues-trump-over-illegal-attempt-to-revoke-states-clean-air-policies/) and are separate from the amendments approved today.  

Following the President’s action, CARB released guidance for manufacturers (https://ww2.arb.ca.gov/sites/default/files/classic/msprog/nvepb/macs/_MACs/mac202503/MAC%20ECCD-2025-03_SSC%20Signed%205.23.25_ADA.pdf) 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.  

Why it matters 

Air pollution is a silent killer that causes heart and lung diseases, and cancer. Over the last 50 years, the state’s clean air efforts have saved $250 billion in health costs through reduced illness including reducing diesel-related cancer risk nearly 80%.   

Although California standards have dramatically improved air quality, the state’s unique geography means continued progress on vehicle emissions is required to achieve state and federal standards.  

Five of the ten cities (https://www.lung.org/research/sota/city-rankings/most-polluted-cities) with the worst air pollution nationwide are in California. Ten million Californians in the San Joaquin Valley and Los Angeles air basins currently live under what is known as “severe nonattainment” conditions for ozone. People in these areas suffer unusually high rates of asthma and cardiopulmonary disease.  

Clean cars and trucks are a critical part of the plan to protect Californians. If upheld, President Trump’s illegal rollback of the state’s waivers would cost Californians an estimated $45 billion in health care costs. If implemented, CARB’s programs would provide $91 billion in cumulative net relief and economic benefits to Californians between next year and 2040.  

What’s next  

In response to illegal federal efforts to revoke California’s clean air waivers, Governor Gavin Newsom signed an executive order (https://www.gov.ca.gov/wp-content/uploads/2025/06/CRA-Response-EO-N-27-25_-bl-formatted-GGN-Signed-6-11-954pmFinal.pdf) 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.   

State agencies have started work in accordance with Governor Newsom’s executive order. The recommendations are being informed by a series of public dialogue sessions (https://ww2.arb.ca.gov/news/california-host-series-public-sessions-effort-advance-progress-zero-emission-vehicle-adoption) that kicked off this week. 

Despite the market uncertainty and disruption brought on by the federal government, California remains steadfast in its commitment to work with manufacturers to keep moving toward a cleaner transportation system while also reducing harmful and costly air pollution. 
 

More Information (https://ww2.arb.ca.gov/our-work/programs/advanced-clean-trucks)