Sts. & Hy. Code, § 30105

The commission may also grant permits to and enter into contracts with steam, electric, bus, railroad, and other transportation companies, public or private, and with any municipal or public corporation, public utility district, or political subdivision for the use of any toll bridge or other toll highway crossing, and for the use of the transportation facilities and the additional transportation facilities thereof, upon such terms and conditions as are mutually agreed upon if, prior to the granting of the permit or the execution of the contract, the commission first determines that the permit or contract is advisable or necessary for the financing of the bridge or other toll highway crossing or for the proper, necessary, or safe use of the bridge and for the best interests of the state.