Cal. Sts. & High. Code § 31230

Any city, county, district, or political subdivision of the state upon the request of the authority may advance or contribute money, rights-of-way, labor, materials, and other property toward the expense of building, acquiring, and maintaining the toll tunnel, 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.