http://www.2theadvocate.com/news/latest/Study-finds-turnpike-cost-triples.html
An A for effort..an F for execution.
You could make a case for upgrading LA 1 and LA 70 to connect with the Sunshine Bridge...but after that, the case dissolves quickly.
Widening I-10 through Baton Rouge and fixing the bottleneck that is the I-10/I-110 Split would be a bigger bang for the buck.
Acutally...completing I-49 South (upgrading US 90 + building the I-49 Connector through Lafayette) at least through Morgan City would be an even better option, The segment from Raceland to New Orleans (less the Westbank Expressway, which does need to be completed) can wait until later.
Anthony