40 U.S.C. § 17509

section 17507(a) of this titleThe heads of executive agencies shall give first priority to meeting the goals established by the President under by reducing the costs of administrative motor vehicles used at the headquarters and regional headquarters of executive agencies, rather than by reducing the costs of motor vehicles used by line agency personnel working in agency field operations or activities.

section 17507(a) of this titleThe President shall require the Administrator of General Services, in cooperation with the Director of the Office of Management and Budget, to prescribe appropriate regulations, standards, and definitions to ensure that executive agencies meet the goals established under in the manner prescribed by subsection (a).