California Code, Vehicle Code - VEH § 35715

(1) Any commercial vehicle coming from an unrestricted highway having ingress and egress by direct route to and from the restricted highway when necessary for the purpose of making pickups or deliveries of goods, wares, and merchandise from or to any building or structure located on the restricted highway or for the purpose of delivering materials to be used in the actual and bona fide repair, alteration, remodeling, or construction of any building or structure upon the restricted highway for which a building permit has previously been obtained.

(2) The operation of ambulances or hearses.

(3) Any vehicle owned, operated, controlled, or used by a public utility in connection with the construction, installation, operation, maintenance, or repair of any public utility facilities.