Cal. Sts. & High. Code § 30500

Any city, county, district, or political subdivision of the state, upon the request of the department or of the commission, may advance or contribute money, rights-of-way, labor, materials, and other property toward the expense of building, acquiring, and maintaining the toll bridge or other highway crossing, and the transportation facilities thereof and thereto referred to in this chapter, and for preliminary surveys and the preparation of plans and estimates of cost thereof and other preliminary expenses. Appropriations for such purposes may be made from any funds available, including highway funds received from the state.