(a) For purposes of certifying your vehicles to greenhouse gas standards, divide your product line into families of vehicles as specified in this section. Your vehicle family is limited to a single model year. Group vehicles in the same vehicle family if they are the same in all the following aspects:
(1) The regulatory sub-category (or equivalent in the case of vocational tractors), as follows:
(i) Vocational vehicles at or below 19,500 pounds GVWR.
(ii) Vocational vehicles (other than vocational tractors) above 19,500 pounds GVWR and at or below 33,000 pounds GVWR.
(iii) Vocational vehicles (other than vocational tractors) above 33,000 pounds GVWR.
(iv) Low-roof tractors above 26,000 pounds GVWR and at or below 33,000 pounds GVWR.
(v) Mid-roof tractors above 26,000 pounds GVWR and at or below 33,000 pounds GVWR.
(vi) High-roof tractors above 26,000 pounds GVWR and at or below 33,000 pounds GVWR.
(vii) Low-roof day cab tractors above 33,000 pounds GVWR.
(viii) Low-roof sleeper cab tractors above 33,000 pounds GVWR.
(ix) Mid-roof day cab tractors above 33,000 pounds GVWR.
(x) Mid-roof sleeper cab tractors above 33,000 pounds GVWR.
(xi) High-roof day cab tractors above 33,000 pounds GVWR.
(xii) High-roof sleeper cab tractors above 33,000 pounds GVWR.
(xiii) Vocational tractors above 26,000 pounds GVWR and at or below 33,000 pounds GVWR. Note that vocational tractor provisions do not apply for vehicles at or below 26,000 pounds GVWR.
(xiv) Vocational tractors above 33,000 pounds GVWR.
(2) Vehicle technology as follows:
(i) Group together vehicles that do not contain advanced or innovative technologies.
(ii) Group together vehicles that contain the same advanced/innovative technologies.
(b) If the vehicles in your family are being certified to more than one FEL, subdivide your greenhouse gas vehicle families into subfamilies that include vehicles with identical FELs. Note that you may add subfamilies at any time during the model year.
(c) Group vehicles into configurations consistent with the definition of ``vehicle configuration'' in Sec. 1037.801. Note that vehicles with hardware or software differences that are related to measured or modeled emissions are considered to be different vehicle configurations even if they have the same GEM inputs and FEL. Note also, that you are not required to separately identify all configurations for certification. See paragraph (g) of this section for provisions allowing you to group certain hardware differences into the same configuration. Note that you are not required to identify all possible configurations for certification; also, you are required to include in your end-of year report only those configurations you produced.
(d) For a vehicle model that straddles a roof-height, cab type, or GVWR division, you may include all the vehicles in the same vehicle family if you certify the vehicle family to the more stringent standards. For roof height, this means you must certify to the taller roof standards. For cab-type and GVWR, this means you must certify to the numerically lower standards.
(e) Divide your vehicles that are subject to evaporative emission standards into groups of vehicles with similar physical features expected to affect evaporative emissions. Group vehicles in the same evaporative emission family if they are the same in all the following aspects, unless we approve a better way of grouping vehicles into families that have similar emission control characteristics:
(1) Method of vapor storage, including the number of vapor storage devices, the working material, and the total working capacity of vapor storage (as determined under 40 CFR 86.132-96(h)(1)(iv)). You may consider the working capacity to be the same if the values differ by 20 grams or less.
(2) Method of purging stored vapors.
(3) Material for liquid and vapor fuel lines.
(f) You may divide your families into more families than specified in this section.
(g) You may ask us to allow you to group into the same configuration vehicles that have very small body hardware differences that do not significantly affect drag areas. Note that this allowance does not apply for substantial differences, even if the vehicles have the same measured drag areas. [76 FR 57398, Sept. 15, 2011, as amended at 78 FR 36392, June 17, 2013; 79 FR 23750, Apr. 28, 2014]