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.