California Air Resources Board Will Workshop Omnibus Regulation Amendments

The California Air Resources Board (CARB) announced that it will hold a public workshop to discuss amendments to its Heavy-Duty (HD) Engine and Vehicle Omnibus (Omnibus) Regulation. The amendments have been proposed following extensive discussion between CARB and the Engine Manufacturers Association (EMA) during 2023, which culminated in CARB agreeing to revise its heavy-duty vehicle emission standards to align more closely with U.S. Environmental Protection Agency standards.

CARB’s Omnibus regulation provides emission standards for manufacturers to certify new truck engines for sale. California first issued its standard for lowering NOx from truck exhaust in 2002, and it has been updated several times. The current Omnibus regulation, approved in December 2021, sets emission standards for engine model years 2024 through 2031. These standards require, among other things, a 90% reduction of NOx emissions from heavy-duty on-road engines compared with existing standards, to be phased in from 2024 to 2031.

Previously, EMA voiced concerns and entered discussions over CARB’s issuance of the heavy-duty truck standards, which resulted in an agreement in July 2023 for CARB to revise the standards. CARB agreed to align key provisions of the Omnibus regulation emissions standards, associated test procedures, and accompanying enforcement provisions for 2027 and subsequent model engines with the corresponding federal requirements. CARB issued the amendments for public comment in December 2023 and is now proposing further stakeholder engagement.

The public notice states that the workshop will cover the following concepts proposed by CARB:

  • modification of various elements of the Omnibus regulation as described in CARB’s agreement with EMA
  • changes to the HD On-Board Diagnostic Real Emissions Assessment Logging parameters
  • changes to HD Emission Warranty Information Report in-use corrective action requirements

The workshop will be held virtually on March 20, 2024. Participants will be allowed to comment and ask questions.

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