There shall be a central garage, service center and motor pool, wherein all automobiles and other vehicles owned by the City shall be maintained, serviced and repaired and from which the head of any department, commission or agency, or his designee, shall requisition the use of any such automobiles or other vehicles as may be required by him or it. The Mayor, or his designee, shall establish and promulgate such rules and regulations respecting such facility as to effect the greatest possible economy and efficiency in its operation.