Ala. Code § 23-1-170

It is the intention of the Legislature by the passage of this article to authorize the incorporation of a public corporation for the following purposes:

(1) To issue bonds to assure the availability of funds for payment of the state’s share of the cost of constructing roads and bridges as shall from time to time be constructed with funds supplied jointly by the state and federal government; and

(2) To construct and maintain, or participate in the construction and maintenance, or lend its aid in construction and maintenance or contract for construction and maintenance of roads and bridges in the State of Alabama, as well as the approaches thereto, including the reconstruction and relocating of approaches, causeways and like or other highway facilities which may, from time to time, be constructed and maintained with funds to be supplied jointly by the state and federal government, together with work incidental and related thereto, through a corporation to be composed of said officials whose incorporation is hereby authorized to vest such corporation with all powers, authorities, rights, privileges and titles that may be necessary to enable it to accomplish such purpose, and to appropriate and pledge funds for the use of such corporation.

All construction and maintenance referred to in this section shall be done under the direction and supervision of the State Department of Transportation. The State Department of Transportation may assign, contract or delegate the work of construction and maintenance under its general powers, subject to approval by the Governor. This article shall be liberally construed in conformity with the said purposes.