The California Air Resources Board (CARB) has postponed action on three major regulatory items originally scheduled for its November 20, 2025, hearing: the On-Road Heavy-Duty Engine and Vehicle Omnibus (Omnibus) regulation, the Low Carbon Fuel Standard (LCFS), and the Emergency Vehicle Emissions regulations. While the hearing will still take place, these items have been removed from the agenda and will be rescheduled at a later date. A future notice will announce the new hearing date. Despite the postponement, the public comment period for these items remains unchanged and will still close on Monday, November 10, 2025. The reason for the postponement remains unclear.

The only issue remaining on the agenda are the proposed amendments to the municipal solid waste landfill methane emissions.

CARB was expected to consider amendments to the Omnibus Regulation that would align California’s heavy-duty engine emissions standards with the federal EPA-NOx rule for 2027 and later model years. These amendments aim to streamline certification, testing, warranty, and compliance procedures, while fulfilling CARB’s commitments under the Clean Truck Partnership.

The proposed LCFS amendments would allow book-and-claim accounting of renewable natural gas (RNG) used to generate electricity for vehicle charging via linear generators. This change is intended to increase the near-term availability of low-carbon electricity for truck refueling to support California’s zero-emission goals.

CARB also planned to make the Emergency Vehicle Emissions Regulations permanent. These regulations clarify that pre-existing engine emission standards remain operative during ongoing litigation over federal Clean Air Act waiver revocations. Filed with the Secretary of State on October 2, 2025, the emergency regulations became effective immediately and can remain in effect for up to 180 days (until March 31, 2026) unless permanently adopted through a formal rulemaking process.

These emergency rules were introduced to address legal uncertainty stemming from federal challenges to California’s authority to enforce its own emissions standards, particularly the revocation of waivers for the Advanced Clean Cars II (ACC II) and Heavy-Duty Low-NOx Omnibus rules. The amendments:

• Reinstate earlier emissions standards (e.g., LEV III and pre-Omnibus) to ensure continuity in vehicle certification and sales.
• Clarify CARB’s enforcement authority, allowing newer standards to be enforced if upheld in court.
• Prevent disruption in California’s vehicle market during litigation.
• Include technical corrections for regulatory consistency.

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