Essentially, once the LA 318 interchange is competed, the only hurdle to US 90 being full Interstate grade between LA 88 in New Iberia and the Calumet intersection just west of Wax Lake Outlet/Calumet Cut would be building an overpass of the L&DRR rail spur just south of the LA 85 interchange near Jeanerette, and the completion of frontage roads between LA 85 and LA 668. Maybe then, LADOTD could pull a TXDOT and ask for I-49 shields??
As for the Patterson/Bayou Vista/Berwick segment of I-49 South, though...I'm not too happy with the downsized proposal that LADOTD now has. The original setup that was approved in the 2008 ROD included an extended elevated section through Patterson/Idlewild/Bayou Vista which allowed for easy access for neighborhoods S of US 90 and the BNSF railline. The current proposal is basically an at-grade conversion of the existing highway, with only Red Cypress Road and Cotten Road as access points between north and south Patterson (via an elevated interchange for Red Cypress and an grade-seperated overpass for Cotten). I know they wanted to save $$$, but I still think they could have done better than that. I think I'll create a new thread later on and elaborate more on this.