40 CFR § 1037.140 - Classifying vehicles and determining vehicle parameters.
(a) Where applicable, a vehicle's roof height and a trailer's length are determined from nominal design specifications, as provided in this section. Specify design values for roof height and trailer length to the nearest inch.
(b) Base roof height on fully inflated tires having a static loaded radius equal to the arithmetic mean of the largest and smallest static loaded radius of tires you offer or a standard tire we approve.
(c) Base trailer length on the outer dimensions of the load-carrying structure. Do not include aerodynamic devices or HVAC units.
(d) The nominal design specifications must be within the range of the actual values from production vehicles considering normal production variability. In the case of roof height, use the mean tire radius specified in paragraph (b) of this section. If after production begins it is determined that your nominal design specifications do not represent production vehicles, we may require you to amend your application for certification under § 1037.225.
(1) Phase 1 and Phase 2 tractors are divided based on GVWR into Class 7 tractors and Class 8 tractors. Where provisions of this part apply to both tractors and vocational vehicles, Class 7 tractors are considered “Medium HDV” and Class 8 tractors are considered “Heavy HDV”. This paragraph (g)(1) applies for electric, hybrid, and non-hybrid vehicles.
(2) Phase 1 vocational vehicles are divided based on GVWR. “Light HDV” includes Class 2b through Class 5 vehicles; “Medium HDV” includes Class 6 and Class 7 vehicles; and “Heavy HDV” includes Class 8 vehicles.
(3) Phase 2 vocational vehicles propelled by engines subject to the spark-ignition standards of 40 CFR part 1036, “Light HDV” includes Class 2b through Class 5 vehicles, and “Medium HDV” includes Class 6 through Class 8 vehicles.
(5) In certain circumstances, you may certify vehicles to standards that apply for a different vehicle service class. For example, see §§ 1037.105(g) and 1037.106(f). If you optionally certify vehicles to different standards, those vehicles are subject to all the regulatory requirements as if the standards were mandatory.
(h) Use good engineering judgment to identify the intended regulatory subcategory (Urban, Multi-Purpose, or Regional) for each of your vocational vehicle configurations based on the expected use of the vehicles.