Iowa Code § 313A.6
The department, its officials, and all state officials are hereby authorized to perform such acts and make such agreements consistent with the law which are necessary and desirable in connection with the duties and powers conferred upon them regarding the construction, maintenance, and operation and insurance of toll bridges or the safeguarding of the funds and revenues required for such construction and the payment of the indebtedness incurred therefor. The department shall adopt such rules and regulations in accordance with the provisions of chapter 17A as it may deem necessary for the administration and exercise of its powers and duties granted by this chapter, and shall prepare annual financial statements regarding the operation of such toll bridges which shall be made available for inspection by the public and by the holders of revenue bonds issued by the department under the provisions of this chapter at all reasonable times.
Iowa Code § 313A.6