La. R.S. 48:858

The governing authority of the parish, at or before the time that such bridge is acquired by the parish by purchase or by expropriation or condemnation, shall determine what repairs, replacements, additions, or betterments will be necessary to place the bridge in safe and efficient condition for the use of the public and shall have an estimate of the cost of the improvements made. The governing authority of the parish shall authorize these improvements before the sale of any bridge revenue bonds for the acquisition of the bridge, and the cost of the improvements shall be paid out of the proceeds of the bonds.