The California Air Resources Board (CARB) has notified the Environmental Protection Agency (EPA) that it has finalized three rulemaking actions--the Advanced Clean Trucks (ACT), Zero Emission Airport Shuttle Bus (ZEAS), and Zero Emission Powertrain (ZEP) Certification regulations. The regulations require manufacturers to produce and sell increasing numbers of zero-emission medium and heavy- duty vehicles, require certain fleets to acquire increasing numbers of zero emitting airport shuttles, and establish new certification requirements and optional emission standards for 2021 and subsequent model year zero-emission medium- and heavy-duty vehicles and the zero- emission powertrains installed on them. By letter dated December 20, 2021, CARB submitted a request that EPA grant waivers of preemption under the Clean Air Act (CAA) This notice announces that EPA has scheduled a public hearing concerning California's request and that EPA is accepting written comment on the request.