Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles-Phase 3

The Environmental Protection Agency (EPA) is promulgating new greenhouse gas (GHG) emissions standards for model year (MY) 2032 and later heavy-duty highway vehicles that phase in starting as early MY 2027 for certain vehicle categories. The phase in revises certain MY 2027 GHG standards that were established previously under EPA's Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles--Phase 2 rule ("HD GHG Phase 2"). This document also updates discrete elements of the Averaging Banking and Trading program, including providing additional flexibilities for manufacturers to support the implementation of the Phase 3 program balanced by limiting the availability of certain advanced technology credits initially established under the HD GHG Phase 2 rule. EPA is also adding warranty requirements for batteries and other components of zero-emission vehicles and requiring customer-facing battery state-of- health monitors for plug-in hybrid and battery electric vehicles. In this action, we are also finalizing additional revisions, including clarifying and editorial amendments to certain highway heavy-duty vehicle provisions and certain test procedures for heavy-duty engines.