La. Roads, Bridges and Ferries § 48:835
The department of highways may enter into written agreements with governing authorities of parishes and municipalities for the construction of tunnels, causeways, and bridges. It may, under such agreements, undertake to perform all or any part of the work so long as the tunnels, causeways, or bridges are part of the highway system. It may contribute services, materials, or funds therefor as long as any such participation is for definitely delineated projects and under a recital from the parishes or municipalities that no funds made available under such agreements shall be used for any purpose other than that specifically set forth in the agreements. The certification by the governing authority of the parish or municipality shall be full and complete authority to the department to pay the department's share of any costs which may be involved.
La. Roads, Bridges and Ferries § 48:835