Cal. Pub. Cont. Code § 20994

Any work or improvement provided for in this act may be located, constructed, and maintained in, along, or across any public road or highway in the County of Los Angeles, in such manner as to afford security for life and property, but the board of supervisors of the district shall restore or cause to be restored such road or highway to its former state as near as may be, so as not to impair its usefulness.