California Waiver Requests for Heavy-Duty Vehicle Emission Regulations

Summary

EPA issued a decision that grants two waivers of preemption regarding four California Air Resource Board (CARB) regulations related to California’s heavy-duty vehicle and engine emission standards. Under the Clean Air Act, states are preempted from adopting and enforcing emission standards for new motor vehicles and new motor vehicle engines. Under section 209 of the Clean Air Act California may seek a waiver of this preemption from EPA. In this instance, CARB submitted three separate waiver requests for six regulations relating to heavy duty vehicles and engines. In three separate Federal Register notices, issued in June 2022, EPA solicited public comment on CARB’s requests. After reviewing the technical information provided by CARB, reviewing comments submitted by the public, and applying the limited authority for review under section 209 of the Clean Air Act, EPA determined it appropriate, at this time, to grant two of the waiver requests and issued one Federal Register notice announcing its decision. CARB is asking EPA for additional time before EPA acts on the waiver request regarding California’s Heavy-duty Omnibus Low NOx regulation (which included two regulations).

These waivers of preemption address the following California programs:

• The 2018 Heavy-duty 2018 Warranty Amendments, which extend the emissions warranty periods for 2022 and subsequent model year on-road heavy-duty diesel engines and for 2022 and subsequent model year diesel vehicles with a gross vehicle weight rating exceeding 14,000 pounds powered by such engines.
• The Advanced Clean Trucks (ACT) Regulation, which requires that manufacturers produce and sell increasing quantities of medium- and heavy-duty zero-emission vehicles (ZEVs) and near zero emission vehicles (NZEVs) in California. This waiver request also includes two additional regulations:
  • The Zero Emission Airport Shuttle Bus (ZEAS) Regulation, which establishes steadily increasing zero-emission airport shuttle fleet composition requirements for airport shuttle fleet owners who service the 13 largest California airports.
  • The Zero Emission Powertrain (ZEP) Certification Regulation, which establishes certification requirements and optional emission standards for 2021 and subsequent model year medium- and heavy-duty ZEVs and the zero-emission powertrains installed in such vehicles.

EPA conducted a virtual public hearing on June 28, 2022, which covered all three proposed actions. The written comment period for these actions closed on August 2, 2022.

Documents

• Notice of Decision (pdf) (390 KB, published April 6, 2023)