21960. (a) The Department of Transportation and local authorities may, by order, ordinance, or resolution, with respect to freeways or designated portions thereof under their respective jurisdictions, to which all rights of access have been acquired, prohibit or restrict the use of the freeways or any portion thereof by pedestrians, bicycles or other nonmotorized traffic or by any person operating a motor-driven cycle or a motorized bicycle. Any such prohibition or restriction pertaining to either bicycles or motor-driven cycles, or to both, shall be deemed to include motorized bicycles; and no person may operate a motorized bicycle wherever such prohibition or restriction is in force. Notwithstanding any provisions of any order, ordinance, or resolution to the contrary, the driver or passengers of a disabled vehicle stopped on a freeway may walk to the nearest exit, in either direction, on that side of the freeway upon which the vehicle is disabled, from which telephone or motor vehicle repair services are available. (b) Such prohibitory regulation shall be effective when appropriate signs giving notice thereof are erected upon any freeway and the approaches thereto. (c) No ordinance or resolution of local authorities shall apply to any state highway until the proposed ordinance or resolution has been presented to, and approved in writing by, the Department of Transportation.