---
kind: "section"
citation: "49 C.F.R. § 525.4"
title: "49"
number: "525.4"
heading: "Definitions."
url: "https://uscodex.org/cfr/49/525.4"
---

# §525.4. Definitions.

- (a) **Statutory terms.**
  - (1) The terms fuel, manufacture, manufacturer, and model year, are used as defined in [section 501](/cfr/49/501.md) of the Act.
  - (2) The terms average fuel economy, fuel economy, and model type are used as defined in [40 CFR 600.002-77](/cfr/40/600.002-77.md).
  - (3) The term automobile means a vehicle determined by the Administrator under [49 CFR part 523](/cfr/49/part523.md) to be an automobile.
  - (4) The term passenger automobile means an automobile determined by the Administrator under [49 CFR part 523](/cfr/49/part523.md) to be a passenger automobile.
  - (5) The term customs territory of the United States is used as defined in [19 U.S.C. 1202](/usc/19/1202.md).
- (b) **Other terms.**
  - (1) The term base level and vehicle configuration are used as defined in [40 CFR 600.002-77](/cfr/40/600.002-77.md).
  - (2) The term vehicle curb weight is used as defined in [40 CFR 85.002](/cfr/40/85.002.md).
  - (3) The term interior volume index is used as defined in [40 CFR 600.315-77](/cfr/40/600.315-77.md).
  - (4) The term frontal area is used as defined in [40 CFR 86.129-79](/cfr/40/86.129-79.md).
  - (5) The term basic engine is used as defined in [40 CFR 600.002-77(a)(21)](/cfr/40/600.002-77.md?p=a-21).
  - (6) The term designated seating position is defined in [49 CFR 571.3](/cfr/49/571.3.md).
  - (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).


## Notes

### Amendments

[42 FR 38376, July 28, 1977, as amended at 44 FR 55579, Sept. 27, 1979]

### Authority

Authority: 15 U.S.C. 2002; 49 CFR 1.50.

### Source

Source: 42 FR 38376, July 28, 1977, unless otherwise noted.

### Amendments

[42 FR 38376, July 28, 1977, as amended at 44 FR 55579, Sept. 27, 1979]