California Code, Vehicle Code - VEH § 21107.6

(a) Any city or county may, by ordinance, find and declare that there are privately owned and maintained roads as described in such ordinance within the city or county which are generally held open to the public for purposes of vehicular travel to serve commercial establishments. Upon enactment by a city or county of such an ordinance, the provisions of this code shall apply to any such privately owned and maintained road. No ordinance shall be enacted under this section without a public hearing thereon and 10 days' prior notice to the owner of the privately owned and maintained road involved.

(b) Notwithstanding the provisions of subdivision (a) no ordinance enacted thereunder shall apply to any road described therein on which the owner has caused to be erected a notice of such size, shape and color as to be readily legible during daylight hours from a distance of 100 feet, to the effect that the road is privately owned and maintained and that it is not subject to public traffic regulations or control.

(c) The department shall not be required to provide patrol or enforce any provisions of this code on any privately owned and maintained road subjected to the provisions of this code under this section, except those provisions applicable to private property other than by action under this section.