Ala. Code § 23-1-37
The State Department of Transportation may work convicts in the construction or maintenance of public roads and bridges of Alabama, as may now or may hereafter be provided by law, or may work convicts in the construction, repairing, or maintaining public roads or bridges by contract or agreement with the Department of Corrections as to the number of convicts required to do such work; provided, that the charge for labor of such convicts shall be in accordance with the terms of the contract which shall be negotiated by and between the Director of the State Department of Transportation and the Department of Corrections, with the approval of the Governor, and no other expense incurred by the use of such convicts shall be chargeable to the State Department of Transportation, except such necessary tools and implements used in the construction, repairing, or maintaining of the public roads and bridges upon which the convicts are employed.
Ala. Code § 23-1-37 (1975)