Subconfiguration means one of the following:
(1) For LDV, LDT, and MDPV, subconfiguration means a unique combination within a vehicle configuration of equivalent test weight, road-load horsepower, and any other operational characteristics or parameters which the Administrator determines may significantly affect fuel economy or CO2 emissions within a vehicle configuration.
(2) For HDV, subconfiguration has the meaning given in § 86.1819-14(d)(12) of this chapter.
40 CFR § 600.002
The following definitions apply throughout this part: