Federal agencies, upon approval from GSA, must provide for any necessary regulation and policing of parking facilities, which may include--
(a) The issuance of traffic rules and regulations;
(b) The installation of signs and markings for traffic control (Signs and markings must conform with the Manual on Uniform Traffic Control Devices published by the Department of Transportation);
(c) The issuance of citations for parking violations; and
(d) The immobilization or removal of illegally parked vehicles.