I have no idea why this road was built.
From: Stephen W. Commiskey
Subject: I-59: Why was it built?
As someone who has traveled I-59 more times than I can remember, perhaps I can provide some justification for its existence.
The road's major discernable purpose, other than pork for Southern politicians, is to connect Birmingham with the world beyond. Birmingham did not exist until the late 1800s, when the discovery of iron ore and coal set off a boom. It remained a steel town until the crash of the American steel market; you can still see the huge, empty USX works from I-59. I-59 served to connect Birmingham to the foundries (and waterways) of Chattanooga, and the coal of West Virginia and Kentucky. It also gave it a connection to New Orleans, which is a much more important port than Mobile, which is the other nearby interstate-accessible port. Finally, I-59 served the purpose of moving U.S. freight traffic off rails and onto roads. A major north-south line runs along that path, as does U.S. 11 (which also follows 75 and 40 into Knoxville, and then joins I-81 for the rest of its run). It also gave the paper companies of southeast Mississippi a handy outlet for their produce (Georgia-Pacific and International Paper both have large operations in SE Miss. and SW Ala.) Oh yes -- and for a large portion of its run, it is coincident with I-20 (about 100 miles). Since so much was built, it was no feat for the politicians to pick up some extra funds to extend it.
Hope this helps!
Stephen W. Commiskey
(proud resident of Mississippi, who goes to college in Virginia -- and is happy to be able to avoid I-85 through North Carolina, despite the fact that taking the mountain route means that he misses the joys of driving at very unsafe speeds on the Perimeter Highway in Atlanta)