Public Workshop on Amendments to the Advanced Clean Cars II Regulations

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October 16, 2023

Public Workshop on Amendments to the Advanced Clean Cars II Regulations

Public Workshop on November 15, 2023

The California Air Resources Board (CARB) invites you to participate in a public workshop to inform potential updates to the Advanced Clean Cars (ACC) regulations. Staff will discuss and seek input on several topics including: concepts for regulatory updates to CARB’s low-emission vehicle (LEV) greenhouse gas (GHG) emission standards for model years beyond 2025; coordination between California’s LEV IV and the proposed federal Tier 4 program for light- and medium-duty vehicle criteria air pollutant requirements; and emerging topics and implementation updates related to CARB’s zero-emission vehicle (ZEV) regulation. Staff will also cover next steps and a potential rulemaking timeline.

Date:                       Wednesday, November 15
Time:                       9:30 a.m. to 11:30 a.m. (Pacific Time)
In-person Location: Mary D. Nichols Campus, Southern California Headquarters
                                Haagen-Smit Auditorium                               
                                4001 Iowa Avenue
                                Riverside, CA 92507
Virtual Location:      Zoom Webinar

The workshop will be recorded. The recording and other workshop materials will be posted at the Advanced Clean Cars website. Staff request stakeholder comments following the workshop be submitted using the workshop comment submittal form by January 15, 2024. Submitted comments can be viewed on CARB’s public comments webpage.

Workshop Information

Virtual Attendance

If you plan to attend virtually, please register for the Zoom Webinar. After you register, you will receive a confirmation email with information about how to join the webinar by computer or telephone.


In-person Attendance

This facility is accessible to persons with disabilities and by public transit. Limited parking is available onsite. In-person attendees are strongly encouraged to carpool or use public transit to get to the facility. For transit information, call (951) 565-5194 or visit the Riverside Transit website.

Registration is not required to attend the workshop in person.

Post-Workshop Tour

For those attending in person, CARB is pleased to offer a tour of CARB’s state-of-the-art emissions laboratory and vehicle test cells, which will begin at 1:30 p.m. and end at approximately 3:30 p.m.. The tour includes walkthroughs of CARB’s test cells that specialize in various engine types and emission sources. Visitors will also see CARB’s vehicle instrumentation labs where technicians and engineers work to equip test vehicles with data acquisition tools.

Space is limited and registration for the tour is mandatory. To participate in the tour, please RSVP by Monday, November 13th at 1:30p.m.. RSVP early to secure your space.

Registration for Tour


If you have questions about the workshop, please contact

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

Background on the Advanced Clean Cars Regulations

In 2012, CARB adopted a set of regulations to control emissions from motor vehicles, collectively called Advanced Clean Cars I (ACC I). These regulations include the LEV III regulation for criteria (LEV III Criteria), GHG (LEV III GHG) emissions, and the ZEV regulation and combine the control of smog-causing (criteria) pollutants and GHG emissions into a single coordinated package of regulations through the 2025 model year.   

In 2022, the Board adopted the ACC II regulations, which establish the next phase of these regulations beginning with the 2026 model year. ACC II increases the stringency of criteria air pollutant emissions standards (LEV IV), updates the ZEV regulation to require 100% ZEV sales by the 2035 model year, and establishes a suite of assurance measures for ZEVs to ensure they can provide enduring emission reductions. CARB did not amend the LEV III GHG emission standards during the ACC II regulatory process.

In May of 2023, U.S. EPA released a proposal that, if adopted, would require manufacturers of light- and medium-duty vehicles to achieve increasingly stringent GHG and criteria air pollutant emissions standards for the 2027-2032 and later model years. As U.S. EPA has not yet finalized its proposal, CARB staff will continue to monitor its rulemaking proceedings and assess potential implications for California’s programs.

Staff are now considering amendments to the ACC II regulations. Staff consider options for the next phase of California’s GHG regulation. Left alone, these emission standards level out in stringency after the 2025 model year and remain in effect for subsequent model years. Staff are evaluating regulatory concepts to support the State’s climate goals that the appropriate stringency and flexibilities of the emission standards and areas where coordination or alignment with federal standards would be beneficial. For criteria air pollutants, staff are monitoring federal proposals for both light- and medium-duty emission standards and will consider potential amendments as appropriate after federal proposals are finalized. For ZEVs, staff are considering new proposals to address emerging ZEV-related issues, such as requirements to help improve interoperability between electric vehicles and charging equipment and data collection to inform a consumer-facing window sticker. Staff are also considering processes to support implementation of the ACC II ZEV regulation, including certain environmental justice provisions.

More Information