La. Roads, Bridges and Ferries § 48:873
Any parish may provide by resolution for the issuance of bridge revenue refunding bonds of the parish for the purpose of refunding any bridge revenue bonds issued under the provisions of this Sub-part and then outstanding. The issuance of the bridge revenue refunding bonds, the maturities, and other details thereof shall be governed by the other provisions of this Sub-part insofar as they apply and by provisions of this Section.
No bridge revenue refunding bonds shall be delivered, unless delivered in exchange for bridge revenue bonds to be refunded thereby, except in the amount necessary to provide for the payment of matured and redeemable bridge revenue bonds or bridge revenue bonds maturing or redeemable including any redemption premium thereon.
No bridge revenue refunding bonds shall be issued, unless issued to refund bridge revenue bonds which have matured or will mature within six months, or are callable, or unless the interest rate of the bridge revenue refunding bonds is at least one-fourth of one per cent less than the interest rate borne by the bridge revenue bonds to be refunded.
La. Roads, Bridges and Ferries § 48:873