Section 531.4 - Definitions(a)Statutory terms.(1) The terms average fuel economy, manufacture, manufacturer, and model year are used as defined in 49 U.S.C. 32901 .(2) The terms automobile and passenger automobile are used as defined in 49 U.S.C. 32901 and in accordance with the determination in part 523 of this chapter.(b)Other terms. As used in this part, unless otherwise required by the context- (1) The term domestically manufactured passenger automobile means the vehicle is deemed to be manufactured domestically under 49 U.S.C. 32904(b)(3) and 40 CFR 600.511-08 . 87 FR 26070 , 7/1/2022; 89 FR 52945 , 8/23/2024