Cal. Gov't Code § 66474.61
In cities having a population of more than 2,800,000, the advisory agency, appeal board or legislative body shall deny approval of a tentative map, or a parcel map for which a tentative map was not required, if it makes any of the following findings:
(g) That the design of the subdivision or the type of improvements will conflict with easements, acquired by the public at large, for access through or use of property within the proposed subdivision. In this connection, the legislative body may approve a map if it finds that alternate easements, for access or for use, will be provided, and that these will be substantially equivalent to ones previously acquired by the public.
This subdivision shall apply only to easements of record or to easements established by judgment of a court of competent jurisdiction and no authority is hereby granted to a legislative body to determine that the public at large has acquired easements for access through or use of property within the proposed subdivision.