49 U.S.C. § 32917
Standards for executive agency automobiles
(a) Definition.—
In this section, “executive agency” has the same meaning given that term in section 105 of title 5 .
(b) Fleet Average Fuel Economy.—
(1)
The President shall prescribe regulations that require passenger automobiles leased for at least 60 consecutive days or bought by executive agencies in a fiscal year to achieve a fleet average fuel economy (determined under paragraph (2) of this subsection) for that year of at least the greater of—
(A)
18 miles a gallon; or
(B)
the applicable average fuel economy standard under section 32902(b) or (c) of this title for the model year that includes January 1 of that fiscal year.
(2)
Fleet average fuel economy is—
(A)
the total number of passenger automobiles leased for at least 60 consecutive days or bought by executive agencies in a fiscal year (except automobiles designed for combat-related missions, law enforcement work, or emergency rescue work); divided by
(B)
the sum of the fractions obtained by dividing the number of automobiles of each model leased or bought by the fuel economy of that model.
( Pub. L. 103–272, § 1(e) , July 5, 1994 , 108 Stat. 1075 .)