In this part:

(1) Administrator
The term "Administrator" means the Administrator of the Environmental Protection Agency.

(2) Certified engine configuration
The term "certified engine configuration" means a new, rebuilt, or remanufactured engine configuration—

(A) that has been certified or verified by—

(i) the Administrator; or

(ii) the California Air Resources Board;

(B) that meets or is rebuilt or remanufactured to a more stringent set of engine emission standards, as determined by the Administrator; and

(C) in the case of a certified engine configuration involving the replacement of an existing engine or vehicle, an engine configuration that replaced an engine that was—

(i) removed from the vehicle; and

(ii) returned to the supplier for remanufacturing to a more stringent set of engine emissions standards or for scrappage.

(3) Eligible entity
The term "eligible entity" means—

(A) a regional, State, local, or tribal agency or port authority with jurisdiction over transportation or air quality;

(B) a nonprofit organization or institution that—

(i) represents or provides pollution reduction or educational services to persons or organizations that own or operate diesel fleets; or

(ii) has, as its principal purpose, the promotion of transportation or air quality; and

(C) any private individual or entity that—

(i) is the owner of record of a diesel vehicle or fleet operated pursuant to a contract, license, or lease with a Federal department or agency or an entity described in subparagraph (A); and

(ii) meets such timely and appropriate requirements as the Administrator may establish for vehicle use and for notice to and approval by the Federal department or agency or entity described in subparagraph (A) with respect to which the owner has entered into a contract, license, or lease as described in clause (i).

(4) Emerging technology
The term "emerging technology" means a technology that is not currently, or has not been previously, certified or verified by the Administrator or the California Air Resources Board but for which an approvable application and test plan has been submitted for verification to the Administrator or the California Air Resources Board.

(5) Fleet
The term "fleet" means one or more diesel vehicles or mobile or stationary diesel engines.

(6) Heavy-duty truck
The term "heavy-duty truck" has the meaning given the term "heavy duty vehicle" in section 7521 of this title.

(7) Medium-duty truck
The term "medium-duty truck" has such meaning as shall be determined by the Administrator, by regulation.

(8) State
The term "State" means the several States, the District of Columbia, the Commonwealth of Puerto Rico, Guam, the United States Virgin Islands, American Samoa, and the Commonwealth of the Northern Mariana Islands.

(9) Verified technology
The term "verified technology" means a pollution control technology, including a retrofit technology or auxiliary power unit, that has been verified by—

(A) the Administrator; or

(B) the California Air Resources Board.