The following restrictions apply for using emission credits:
(a) Averaging sets. Except as specified in paragraph (b) of this section, emission credits may be exchanged only within an averaging set. There are three principal averaging sets for vehicles subject to this subpart.
(1) Vehicles at or below 19,500 pounds GVWR that are subject to the standards of Sec. 1037.105.
(2) Vehicles above 19,500 pounds GVWR but at or below 33,000 pounds GVWR.
(3) Vehicles over 33,000 pounds GVWR.
(4) Note that other separate averaging sets also apply for emission credits not related to this subpart. For example, under Sec. 1037.104, an additional averaging set comprises all vehicles subject to the standards of that section. Separate averaging sets also apply for engines under 40 CFR part 1036, including engines used in vehicles subject to this subpart.
(b) Credits from hybrid vehicles and other advanced technologies. The averaging set restrictions of paragraph (a) of this section do not apply for credits generated under Sec. 1037.104(d)(7), Sec. 1037.615 or 40 CFR 1036.615 from hybrid vehicles with regenerative braking, or from other advanced technologies.
(1) The maximum amount of credits you may bring into the following service class groups is 60,000 Mg per model year:
(i) Spark-ignition engines, light heavy-duty compression-ignition engines, and light heavy-duty vehicles. This group comprises the averaging set listed in paragraphs (a)(1) of this section and the averaging set listed in 40 CFR 1036.740(a)(1) and (2).
(ii) Medium heavy-duty compression-ignition engines and medium heavy-duty vehicles. This group comprises the averaging sets listed in paragraph (a)(2) of this section and 40 CFR 1036.740(a)(3).
(iii) Heavy heavy-duty compression-ignition engines and heavy heavy-duty vehicles. This group comprises the averaging sets listed in paragraph (a)(3) of this section and 40 CFR 1036.740(a)(4).
(2) The limit specified in paragraph (b)(1) of this section does not limit the amount of advanced technology credits that can be used within a service class group if they were generated in that same service class group.
(c) Credit life. Credits expire after five years.
(d) Other restrictions. Other sections of this part specify additional restrictions for using emission credits under certain special provisions.