Ala. Code § 33-16-9
The aggregate monetary obligation that the authority may incur in connection with its contracts (other than contracts of the type described in the next succeeding paragraph) shall not at any time exceed the sum of:
No contract which is subject to the foregoing restriction and which involves the expenditure of money, whether now or later, shall be approved or ratified by the board of directors unless the resolution approving or ratifying the same shall include a determination that there will be compliance with the preceding limitation when the amount of the obligation of the contract in question has been added to the already existing obligations of the authority. This determination by the board of directors shall be conclusive of the question of compliance.
The restriction set forth in the preceding paragraph shall not apply to any contract between the authority and the United States, or an agency thereof, pursuant to which the authority agrees to satisfy the requirements of local contribution and participation with respect to a project related to the development of the waterway. Prior to the execution of any such contract between the authority and the United States, or an agency thereof, the board of directors of the authority shall adopt a resolution approving such contract, which resolution shall include a determination that the moneys expected to be available to the authority for the payment of its monetary obligations (if any) under such contract will be sufficient to pay such monetary obligations.
Except as otherwise provided in the last paragraph of this section, all contracts of the authority for the construction, reconstruction, relocation, maintenance and operation of highways, roads and bridges, and work incidental or related thereto, and the acquisition of property necessary therefor, shall be in writing, shall be subject to the rules and regulations and shall be let under the supervision of the Highway Department and shall be subject to approval by the Governor and by the Highway Department. All work provided for in any such contract shall be supervised by the highway department. All persons engaging in the supervision or performance of any work involving highways, roads and bridges that may be done by the authority without the award of a contract therefor shall be employees of the Highway Department.
Except as otherwise provided in the last paragraph of this section, all contracts of the authority for the construction, reconstruction or relocation of any facilities or structures and all purchases of equipment by the authority shall be made on the basis of competitive bidding in the manner and according to the procedures provided in Sections 39-2-1 through 39-2-13 and 41-16-20 through 41-16-32, and any other applicable statutes.
In connection with the construction, reconstruction or relocation of highways, roads and bridges, and the acquisition of property necessary therefor, the authority may enter into contracts with the United States, or an agency thereof, pursuant to which the work related to any such construction, reconstruction or relocation shall be performed, and any property necessary therefor shall be acquired, by the United States, or an agency thereof, or by one or more contractors selected by the United States, or an agency thereof. Any such contract between the authority and the United States, or an agency thereof, shall not be subject to the requirements and restrictions (including, without limitation, the requirements with respect to competitive bidding) set forth in the two immediately preceding paragraphs of this section.
Ala. Code § 33-16-9 (1975)