49 C.F.R. § 525.4
Definitions.
Cite as 49 C.F.R. § 525.4 (2026)
(a)
Statutory terms.
(1) The terms
fuel,
manufacture,
manufacturer,
and
model year,
are used as defined in section 501 of the Act.
(2) The terms
average fuel economy, fuel economy,
and
model type
are used as defined in 40 CFR 600.002-77.
(3) The term
automobile
means a vehicle determined by the Administrator under 49 CFR part 523 to be an automobile.
(4) The term
passenger automobile
means an automobile determined by the Administrator under 49 CFR part 523 to be a passenger automobile.
(5) The term
customs territory of the United States
is used as defined in 19 U.S.C. 1202.
(b)
Other terms.
(1) The term
base level
and
vehicle configuration
are used as defined in 40 CFR 600.002-77.
(2) The term
vehicle curb weight
is used as defined in 40 CFR 85.002.
(3) The term
interior volume index
is used as defined in 40 CFR 600.315-77.
(4) The term
frontal area
is used as defined in 40 CFR 86.129-79.
(5) The term
basic engine
is used as defined in 40 CFR 600.002-77(a)(21).
(6) The term
designated seating position
is defined in 49 CFR 571.3.
(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).
(Authority: Sec. 301, Pub. L. 94-163, 89 Stat. 871 (15 U.S.C. 2002); delegation of authority at 41 FR 25015, June 22, 1976; sec. 9, Pub. L. 89-670, 80 Stat. 981 (49 U.S.C. 1657))
[42 FR 38376, July 28, 1977, as amended at 44 FR 55579, Sept. 27, 1979]
- Cross-references to the US Code
- 15:200219:1202.49:1657
- Cross-references to the CFR
- 40:600.002-7740:600.002-77.40:600.315-77.40:85.002.40:86.129-79.49:571.3.