La. Roads, Bridges and Ferries § 48:1158
Whenever all indebtedness incurred by an Authority, including interest thereon, shall have been fully paid and satisfied, or duly provided for in the manner specified in the resolution, indenture, agreement or other proceedings under or pursuant to which such indebtedness was incurred, the Department of Highways may continue the operation of such bridge as a toll bridge, and may charge tolls for the use thereof at such rates as it shall exclusively determine, until all advances made from the State Highway Fund with respect to such bridge, including the cost of construction of connecting highways and approaches thereto, shall have been refunded to the State Highway Fund or, in the discretion of the Department of Highways, it may thereupon operate such bridge as a free bridge. After all such advances have been refunded to the State Highway Fund, the said bridge shall be operated as a toll free bridge; provided, however, if an authority pursuant to law constructs and operates more than one bridge and secures indebtedness incurred by the authority to pay the cost of construction of one or more of such bridges, including the interest thereon, by a pledge of all or part of the combined tolls, charges and fares derived by the authority from its operation of such bridges, or any of them, and any other funds and revenues received by the authority pursuant to law, all such bridges, the combined tolls and other revenues of which are pledged to the payment of such indebtedness, shall be operated by such authority as toll bridges until all such indebtedness, including interest thereon, shall have been fully paid or satisfied, or duly provided for in the manner specified in the resolution, indenture, agreement or other proceedings under or pursuant to which such indebtedness was incurred. When an authority deems it necessary and advisable in the public interest and pursuant to law to undertake the construction of an additional bridge or bridges and to pay the cost of construction thereof by incurring indebtedness secured by a pledge of all or any part of the combined tolls, charges and other funds and revenues of such authority, the Department of Highways is authorized and directed to enter into amendments and modifications of any existing contract or contracts previously entered into with such authority pursuant to this Part if such amendment and modification is required in order to permit the operation of all or any of such bridges as toll bridges until all such indebtedness shall have been fully paid and satisfied, or duly provided for.
La. Roads, Bridges and Ferries § 48:1158