California Code, Streets and Highways Code - SHC § 985

The board of supervisors may construct, install and maintain cattle guards on or adjacent to the county highways.  The cost of constructing, installing, and maintaining such cattle guards may be paid from the general county fund.

The board of supervisors may, under such restrictions, plans and specifications as it may deem proper, permit any property owner to construct, install or maintain at his own expense, cattle guards on or adjacent to any county highway.  The construction and maintenance of such cattle guards shall be under the direction and supervision of the board of supervisors, and they may require such bond as they deem proper as a condition of the granting of permission to erect such cattle guard.