Cal. Sts. & High. Code § 31140

Whenever the authority determines that it is for the best interests of the public highways in the state that the toll tunnel be constructed and operated by the authority, based upon preliminary estimates of the cost of construction thereof, an estimate of the amount required to be raised for that purpose by the issuance of revenue bonds, and a statement of the probable amount of money, property, materials, or labor to be contributed from other sources in aid of the construction prepared by its staff, it shall adopt a resolution declaring that public interest and necessity require the construction of the toll tunnel and authorizing the issuance of revenue bonds for the purpose of obtaining funds in an amount not in excess of that estimated to be required for the construction thereof.