I drove through Oak Park (just south of I-16) on Thursday. US 1 traffic has been moved to a new bypass around Oak Oark, as much as half a mile west of town, between GA 46 and the south city limits. At least the south end of the old route through town dead-ends in a cul-de-sac, so through traffic can't stay on the old route, and I doubt the old route will become a new US 1 business route.
There are two travel lanes southbound, and one northbound, on the new bypass. Construction is continuing to finish the project, so the reroute might not yet be "official", nor has GDOT sought AASHTO approval (assuming it thinks approval is needed). Also, online mapping hadn't caught up to the change last I looked, though some satellite imagery shows the bypass under construction.