In the absence of an agreement between the department and an adjoining state to the contrary, the department may accomplish any construction or maintenance upon that portion of any interstate bridge which is located within the State of Nebraska by any of the following methods which, in the opinion of the department, shall be to the best interests of the State of Nebraska in regard to economy, ease of operation, and traffic control:
(1) Utilization of its own personnel, material, and equipment;(2) utilization of its own personnel, and rental, lease, or purchase of the necessary equipment and material;(3) letting contracts for such construction or maintenance to any person qualified; or(4) utilization of any combination of such methods; Provided, that all construction or maintenance done by the department which involves the use of funds of both the State of Nebraska and the United States shall be let by contract in the manner provided by the provisions of section 39-8,105.Neb. Rev. Stat. §§ 39-8,104
Laws 1959, c. 175, § 14, p. 638.