Pub. L. 82-451, tit. IV, sec. 409

Sec. 409. Except for the car officially assigned to the Secretary of Agriculture, no part of any appropriation contained in this Act shall be used to pay the compensation of any civilian employee of the Government whose principal duties consist of acting as chauffeur of any Government-owned passenger motor vehicle (other than a bus or ambulance), unless such appropriation is specifically authorized to be used for paying the compensation of employees performing such duties.