California’s Air Resources Board (CARB) held a public workshop Wednesday where it announced its intent to amend its future Heavy-Duty Engine and Vehicle Omnibus regulations to better align with the Environmental Protection Agency’s (EPA) 2027 model year engine requirements.
CARB stated during the workshop it does not intend to amend its existing model year (MY) 2024 to 2026 regulations, but believes its amendments for MY 2027 and subsequent model years will better connect CARB’s future Omnibus regulations with Federal efforts, and could bring 50-state certified equipment back to the marketplace.
On the latter, CARB’s Paul Adnani said OEMs will make the ultimate decision on whether the engines they bring to market for MY 2027 will be nationwide solutions or not. Adnani says under CARB’s proposed amendment, its testing certification for MY 2027 combustion- and spark-ignited engines will align with EPA’s 2027 plans. But CARB will still certify engines independently (and in-use standards could still differ slightly). Adnani said manufacturers will decide if they want their California solutions to be used nationally or just in the state.
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Added CARB’s Kim Heroy-Rogalski, “There are provisions for in-use testing [for California] that could be different [than EPA regulations], but an OEM could say they’re going to use the California testing and that would be seamless.”
Aligning with EPA 2027 regulations also would require updates of CARB’s Averaging, Banking and Trading (ABT) program, said CARB’s Daniel Hawelti. Under its proposed changes, Hawelti said CARB it would merge its California ABT program with the Federal ABT program beginning with MY 2027, and allow the use of credits accrued under the Federal ABT program to certify 50-state engine families in California. He said credits from zero-emission powertrains would not be permitted for MY 2027 and later, but no ABT program would exist moving forward for HC, CO or PM for MY 2027 and later engines.
Hawelti also noted Wednesday that as part of the board’s proposal to largely align with EPA NOx rule, CARB is not committing to issue “deemed to comply certifications” based on EPA certifications. Finally, he said CARB will maintain separate programs for its aforementioned certification program, OBD program, emissions warranty information reporting program HD in-use compliance program and Clean Idle Label requirement, which will remain mandatory and not voluntary as it is under the EPA rule making.
CARB will now accept industry feedback on its proposed changes before holding a second workshop, finalizing its rulemaking package and hold a 45-day notice posting. CARB said a board hearing is tentatively scheduled for November 2025 to finalize any changes.
