Vehicle service class
Vehicle service class has the same meaning for vehicles as specified in 40 CFR 1037.140. Fuel consumption standards and other provisions of this part apply to specific vehicle service classes for tractors and vocational vehicles as follows:
(1) Phase 1 and Phase 2 tractors are divided based on GVWR into Class 7 tractors and Class 8 tractors. Where provisions apply to both tractors and vocational vehicles, Class 7 tractors are considered medium heavy-duty “MHD” vehicles and Class 8 tractors are considered heavy heavy-duty “HHD” vehicles.
(2) Phase 1 vocational vehicles are divided based on GVWR. Light heavy-duty “LHD” vehicles includes Class 2b through Class 5 vehicles; medium heavy-duty “MHD” vehicles includes Class 6 and Class 7 vehicles; and heavy heavy-duty “HHD” vehicles includes Class 8 vehicles.
(3) Phase 2 vocational vehicles with spark-ignition engines are divided based on GVWR. Light heavy-duty “LHD” vehicles includes Class 2b through Class 5 vehicles, and medium heavy-duty “MHD” vehicles includes Class 6 through Class 8 vehicles.
(4) Phase 2 vocational vehicles with compression-ignition engines are divided as follows:
(i) Class 2b through Class 5 vehicles are considered light heavy-duty “LHD” vehicles.
(ii) Class 6 through 8 vehicles are considered heavy heavy-duty “HHD” vehicles if the installed engine's primary intended service class is heavy heavy-duty (see 40 CFR 1036.140). All other Class 6 through Class 8 vehicles are considered medium heavy-duty “MHD” vehicles.
(5) In certain circumstances, manufacturers may certify vehicles to standards that apply for a different vehicle service class such as allowed in § 535.5(b)(6) and (c)(7). If manufacturers optionally certify vehicles to different standards, those vehicles are subject to all the regulatory requirements as if the standards were mandatory.