The Story of California’s Advanced Clean Trucks Regulation

New CLEE report & webinar tells the story of this first-of-its-kind supply-side regulation for zero-emission trucks

California has been a global pioneer on electric vehicles, and that leadership extends to zero-emission trucks. To address the pollution and disproportionate impacts on disadvantaged communities, the California Air Resources Board (CARB) adopted the first-of-its-kind Advanced Clean Trucks (ACT) regulation in 2020. This landmark standard required truckmakers to begin selling zero-emission versions (such as battery electric or hydrogen fuel cell models) starting in 2024, with increasing percentages through 2035. It also included a credit-deficit trading system, in which companies not in compliance could purchase credits from companies that exceeded the target for a given compliance period.

Though the Advanced Clean Trucks regulation is now the subject of litigation regarding its current status, due to a June 2025 vote by the U.S. Congress to revoke the federal waiver to enforce it, the story of its development holds many lessons for regulators and stakeholders around the world considering similar policies. Based on exclusive interviews with advocates, industry leaders and officials involved in the rule-making, as well as a comprehensive review of the public documents associated with that process, the new CLEE report California’s Advanced Clean Trucks Regulation: Key Decisions and Stakeholder Impacts offers a thorough examination of how the California Air Resources Board developed the regulation, including the key decision points, as well as the influence stakeholders had in the process. 

Key decision points in the development of the regulation include: 

• • The California Air Resources Board strengthened the zero-emission truck percentage sales targets and years of compliance from the original proposal, based on technical data on feasibility and cost, as well as a coordinated communications campaign by a coalition of advocates and progressive businesses that prevailed over the objections of the trucking industry. 

• • The board granted the trucking industry enhanced flexibility on compliance, mainly through a complex but ultimately less prescriptive system of trading and purchasing credits to meet compliance obligations, while placing more stringent targets in place.

• • In the process of developing the rule, the board collected new data about fleet vehicle operations, including the type of vehicles large employers possessed, how they operated them, the mileage distribution of the fleets, and the portion of the fleets that returned to base, as well as purchasing patterns through the Advanced Clean Trucks’ Large-Entity Reporting Requirement—information that subsequently informed the future Advanced Clean Fleets regulation.

Ultimately, the story of the Advanced Clean Trucks regulation is one of increasing ambition, largely based on new information about battery innovation and faster-than-expected deployment of early zero-emission truck models, along with persuasive stakeholder engagement from environmental justice, public health, labor and community-based advocates, including progressive businesses. While the California Air Resources Board rejected the legacy truckmaker industry’s efforts to significantly weaken the standard by providing alternative means of compliance beyond manufacturing and selling zero-emission trucks, the agency did grant the legacy truckmakers more flexibility on compliance, in response to concerns about the lack of charging infrastructure, costs, and other challenges that the agency deemed to be valid.

Register for the upcoming free webinar on May 6th, 2026 from 9:00-10:00 am PT, featuring a panel discussion with key stakeholders during the development of California’s Advanced Clean Trucks Regulation: 

• Katherine Garcia, Director of the Clean Transportation for All Campaign, Sierra Club
• Jimmy O’Dea, Acting Deputy Director, Caltrans (former Union of Concerned Scientists)
• Michael Geller, Deputy Director, Manufacturers of Emission Controls Association
• Chloé F. Smith, Research Fellow, UC Berkeley Law’s Center for Law, Energy, and the Environment (CLEE)
• Ethan Elkind (Moderator), Director of the Climate Program, CLEE

California Air Resources Board, Clean Trucks Standards, public health, toxic air pollution, Transportation, Zero-emission trucks