49 CFR §525.4

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗

(a)Statutory terms.
1. (1)The terms fuel, manufacture, manufacturer, and model year, are used as defined in section 501 of the Act.
2. (2)The terms average fuel economy, fuel economy, and model type are used as defined in 40 CFR 600.002-77.
3. (3)The term automobile means a vehicle determined by the Administrator under 49 CFR part 523 to be an automobile.
4. (4)The term passenger automobile means an automobile determined by the Administrator under 49 CFR part 523 to be a passenger automobile.
5. (5)The term customs territory of the United States is used as defined in 19 U.S.C. 1202.
(b)Other terms.
1. (1)The term base level and vehicle configuration are used as defined in 40 CFR 600.002-77.
2. (2)The term vehicle curb weight is used as defined in 40 CFR 85.002.
3. (3)The term interior volume index is used as defined in 40 CFR 600.315-77.
4. (4)The term frontal area is used as defined in 40 CFR 86.129-79.
5. (5)The term basic engine is used as defined in 40 CFR 600.002-77(a)(21).
6. (6)The term designated seating position is defined in 49 CFR 571.3.
7. (7)As used in this part, unless otherwise required by the context:

Act means the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513), as amended by the Energy Policy and Conservation Act (Pub. L. 94-163); Administrator means the Administrator of the National Highway Traffic Safety Administration; Affected model year means a model year for which an exemption and alternative average fuel economy standard are requested under this part; Production mix means the number of passenger automobiles, and their percentage of the petitioner's annual total production of passenger automobiles, in each vehicle configuration which a petitioner plans to manufacture in a model year; and Total drive ratio means the ratio of an automobile's engine rotational speed (in revolutions per minute) to the automobile's forward speed (in miles per hour).