California Code, Streets and Highways Code - SHC § 101.9

(a) The department shall adopt rules and regulations to allow, in rural areas, the placement, on interstate and primary highways near public exits, of guide signs indicating the existence, within one-half mile of that exit, of a fire station which is open 24 hours each day of the year.

(b) Upon the request of the Department of Forestry and Fire Protection or a city or county, the department may place and maintain the signs in accordance with the adopted rules and regulations. The department shall bear the costs of placing and maintaining the signs.