; (ii) at least 75 percent shall be zero-emission vehicles or plug-in hybrids in fiscal years 2035 through 2049; and (iii) 100 percent shall be zero-emission vehicles in fiscal year 2050 and thereafter. (B) Medium- and heavy-duty vehicles The following percentages of the total number of medium- and heavy-duty vehicles acquired by a Federal entity for a Federal fleet shall be alternative fueled vehicles: (i) At least 20 percent in fiscal years 2026 through 2029. (ii) At least 30 percent in fiscal years 2030 through 2039. (iii) At least 40 percent in fiscal years 2040 through 2049. (iv) At least 50 percent in fiscal year 2050 and thereafter. (2) Exception The Secretary, in consultation with the Administrator of General Services where appropriate, may permit a Federal entity to acquire for a Federal fleet a smaller percentage than is required in paragraph (1) for a fiscal year, so long as the aggregate percentage acquired for each class of vehicle for all Federal fleets in the fiscal year is at least equal to the required percentage. (3) Definitions In this subsection: (A) Federal fleet The term Federal fleet means a fleet of vehicles that are centrally fueled or capable of being centrally fueled and are owned, operated, leased, or otherwise controlled by or assigned to any Federal executive department, military department, Government corporation, independent establishment, or executive agency, the United States Postal Service, the Congress, the courts of the United States, or the Executive Office of the President. Such term does not include— (i) motor vehicles held for lease or rental to the general public; (ii) motor vehicles used for motor vehicle manufacturer product evaluations or tests; (iii) law enforcement vehicles; (iv) emergency vehicles