California Code, Streets and Highways Code - SHC § 26230

After any boulevard has been completely constructed the commission may, at its option, convey all the right, title and interest of the district in and to that boulevard to the county within which the district is situated, if the board of supervisors of the county consents to and accepts the conveyance and agrees to maintain the boulevard as a boulevard and as part of the county highway system. All boulevards so conveyed shall be held by the county as county boulevards without any further liability or responsibility on the part of the district. No such conveyance shall affect the liability of the district for, or any bonds previously issued by the district.