Veh. Code, § 21107.7

(a) Any city or county may, by ordinance or resolution, find and declare that there are privately owned and maintained roads as described in the ordinance or resolution within the city or county that are not generally held open for use of the public for purposes of vehicular travel but, by reason of their proximity to or connection with highways, the interests of any residents residing along the roads and the motoring public will best be served by application of the provisions of this code to those roads. No ordinance or resolution shall be enacted unless there is first filed with the city or county a petition requesting it by a majority of the owners of any privately owned and maintained road, or by at least a majority of the board of directors of a common interest development, as defined by Section 4100 or 6534 of the Civil Code, that is responsible for maintaining the road, and without a public hearing thereon and 10 days’ prior written notice to all owners of the road or all of the owners in the development. Upon enactment of the ordinance or resolution, the provisions of this code shall apply to the privately owned and maintained road if appropriate signs are erected at the entrance to the road of the 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 subject to the provisions of this code. The city or county may impose reasonable conditions and may authorize the owners, or board of directors of the common interest development, to erect traffic signs, signals, markings, and devices which conform to the uniform standards and specifications adopted by the Department of Transportation.

(b) 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.

(c) As used in this section, “privately owned and maintained roads” includes roads owned and maintained by a city, county, or district that are not dedicated to use by the public or are not generally held open for use of the public for purposes of vehicular travel.