La. Roads, Bridges and Ferries § 48:886
The governing authority of any parish issuing its bonds pursuant to the provisions of this Sub-part shall do all acts necessary in the construction or acquisition, maintenance and operation of any bridge to the end that the bridge may be operated free of tolls as early as possible and practicable, subject only to the express limitations of this Sub-part and the limitations of the other laws and constitutional provisions applicable thereto.
When the particular bonds issued for any bridge or bridges and the interest thereon has been paid or a sufficient amount has been provided for their payment and continues to be held for that purpose, the parish issuing the bonds shall cease to charge tolls for the use of the bridge or bridges and the bridge or bridges shall be free, unless tolls are required for maintaining, repairing, and operating the bridge or bridges due to the lack of funds from other sources than tolls. However, the provisions of this Section do not apply to common carriers, transportation companies, bus lines, and anyone transporting passengers or freight for hire, but apply only to the use of the highway portion of the bridge by the traveling public. As respects other than the latter use, the parish may continue to fix and collect such tolls and charges as it considers in the public interest.
La. Roads, Bridges and Ferries § 48:886