Advanced Clean Fleets Regulation Updates

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September 29, 2023

Advanced Clean Fleets Regulation Updates

On September 29, 2023, the Office of Administrative Law approved the Advanced Clean Fleets (ACF) Regulation, which means the regulation is effective October 1, 2023. CARB has been developing and posting compliance assistance resources and has recently developed a searchable database that fleets can use to search for answers to their questions on the ACF regulation.

Searchable FAQ

Key upcoming requirements for the ACF regulation are:

  • Drayage Trucks: Applies to drayage trucks transporting cargo to and from California’s intermodal seaports and railyards. Drayage trucks with an internal combustion engine that intend to begin or continue operations at a California seaport or intermodal railyard must register in the Truck Regulation Upload, Compliance, and Reporting System (TRUCRS) database no later than December 31, 2023.
  • State and Local Government Fleets: Applies to any state or local government agency with jurisdiction in California. Compliance requirements begin January 1, 2024 and reporting is due April 1, 2024.
  • High Priority Fleets: Applies to fleets that own, operate, or direct the operation of at least 1 vehicle in California, and that have either $50 million or more in gross annual revenue, or that own, operate, or direct the operation of a total of 50 or more vehicles, and federal government agencies. Compliance requirements begin January 1, 2024 and reporting is due February 1, 2024.
  • Fleet owners that purchase new vehicles in California are not affected because manufacturers can only sell California certified engines for new vehicles that are sold into California. However, the California certified ICE engine requirement will not be enforced for vehicles with 2024 and 2025 model years engines that are purchased outside of California and are operated in California as part of the California fleet.

More details on the regulation can be found on CARB’s ACF website.

Additional resources can be found at ZEV TruckStop.


The ACF Regulation (California Code of Regulations, Title 13, Sections 2013, 2013.1, 2013.2, 2013.3, 2013.4, 2014,2014.1, 2014.2, 2014.3, 2015, 2015.1, 2015.2, 2015.3, 2015.4, 2015.5, 2015.6, and 2016) is the latest development in CARB’s decades‑long history of setting increasingly stringent emission standards for mobile sources that are needed to protect the public health and welfare of Californians by improving air quality and by mitigating the harms posed by greenhouse gases. The ACF regulation complements CARB’s recently adopted Advanced Clean Trucks regulation, and will help advance the introduction of zero-emission technologies into California’s truck and bus fleets requiring fleets that are well suited for electrification to transition to zero-emission vehicles (ZEV) through requirements to both phase-in the use of ZEVs for targeted fleets and requirements that manufacturers only manufacture ZEV trucks starting in the 2036 model year. Achieving these and other milestones will contribute to meeting the goals in the Governor’s Executive Order N-79-20 and result in cleaner, more healthful air for all Californians, especially those communities most heavily impacted by air pollution. The ACF regulation is expected to introduce 1,690,000 ZEVs into the California fleet by 2050. Additionally, the ACF regulation is expected to result in $26.5 billion in statewide health benefits from improved air quality and save fleet owners an estimated $48.0 billion through 2050.

Achieving California’s long-term air quality, climate, and public health goals will require medium- and heavy-duty vehicles to significantly reduce their emissions, such as by embracing commercially available zero-emission technologies where feasible, and by using near-zero-emission technologies powered by clean, low‑carbon renewable fuels everywhere else. Promoting the development and use of zero-emission trucks will contribute to the goals set by the Governor’s Executive Order N-79-20 and the Sustainable Freight Action Plan, and will help achieve emission reductions as outlined in the State Implementation Plan, Senate Bill (SB) 350 (de León, Chapter 547, Statutes of 2015), Assembly Bill 32 (Nuñez, Chapter 488, Statutes of 2006), and SB 32 (Pavley, Chapter 249, Statutes of 2016), and Assembly Bill 1279. The ACF regulation is an important part of California’s broader strategy to increase clean, affordable transportation options such as zero-emission technologies, innovative methods to improve freight activity, and transportation system efficiency in California.


For question on the ACF regulation, contact the Advanced Clean Fleets team. To receive updates on the ACF regulation, visit the Advanced Clean Fleets website and sign up to receive future updates and notices of upcoming events.

If you require a special accommodation or need this document in an alternate format (i.e., Braille, large print) or another language, please contact Mr. Harinder Phagura, as soon as possible. TTY/TDD/Speech to Speech users may dial 711 for the California Relay Service.