California’s Advanced Clean Trucks Regulation

Key Decisions and Stakeholder Impact

April 2026

Truck pollution is a silent public health crisis. In California, air pollution from heavy-duty vehicles are responsible for thousands of asthma cases and hospital visits annually. This burden falls disproportionately on lower-income communities situated near highways, warehouses, and freight corridors. Beyond the local health impacts, these trucks are significant contributors to greenhouse gas emissions.

To address the pollution and disproportionate impacts on disadvantaged communities and to meet its climate goals, the California Air Resources Board (CARB) adopted the Advanced Clean Trucks (ACT) regulation in 2020. This standard required truckmakers to begin selling zero-emission versions 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.

The Advanced Clean Trucks regulation represented the first-of-its kind, and our new CLEE report, California’s Advanced Clean Trucks Regulation: Key Decisions and Stakeholder Impact, seeks to explain how CARB developed it from its initial statement of reason to the final version, as well as the influence stakeholders had in the process. The story includes key decision points and takeaways of CARB’s Advanced Clean Trucks regulation: 

• CARB 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.

The goal of this CLEE report is to share the story of how CARB developed and ultimately adopted the Advanced Clean Trucks regulation, and the lessons learned for jurisdictions designing similar clean truck policies and for interested stakeholders who could benefit from California’s experience, regardless of the final outcome of the original regulation.

Read the full report here.