La. Roads, Bridges and Ferries § 48:862
The governing authority of any parish may provide by resolution at one time and from time to time for the issuance of bridge revenue bonds of the parish for the purpose of paying the cost of any one or more of such bridges. This resolution shall recite an estimate of the cost. The principal and interest of the bonds shall be secured by a conventional mortgage upon the bridge and by pledge of the revenues thereof sufficient in amount to pay the principal and interest on the bonds as they severally mature. The bonds and the coupons attached thereto shall not be a charge upon any other income or revenue of any parish, the state of Louisiana, or any agency or political subdivision thereof, nor shall said bonds and coupons constitute an indebtedness or pledge of, or affect the general credit of, any parish, the state of Louisiana, or any agency or political subdivision thereof, within the meaning of any constitutional or statutory limitation of indebtedness. The principal and interest of the bonds may be made payable in any lawful medium.
In the discretion of the governing authority of the parish, bonds of a single issue may be issued for the purpose of paying the cost of any one or more bridges.
La. Roads, Bridges and Ferries § 48:862