Looking there's a total dearth of any BGSs telling you what the mainline is and where it goes - it's all those reassurance signs to know the number. All the intersecting roads (save I-65) have GMSV that's at least a couple of years old.
"I'm guessing straight on to Birmingham here at this major junction with US45?".
Here's a photo of I-22 shields on a side road:
https://c1.staticflickr.com/8/7510/15306956713_9ceb3d5c06_m.jpgFrom the thread Oscar mentions (which comes with this warning "Warning: this topic has not been posted in for at least 120 days. Unless you're sure you want to reply, please consider starting a new topic.")
If you can verify that it's signed as vanilla I-22 in more than just Jefferson County, then go for it.
I drove that segment on Oct. 26 so I can confirm, yes, it is open and signed and I now have a bit of I-22 on my list. 
So signage shows that it is
de facto I-22. The
de jure is also solid, with confusing coming from
AL's recent AASHTO request to convert Future Interstate 22 between Birmingham and exit 93 in Birmingham to I-22 proper. It strikes me that this is 2.879 miles of renumbering that only increased interstate mileage in the state by 0.26 miles (matching the route log on page 8's total of 96.48) is about correcting the length figure more than formalising the missing link's status as interstate.
It also clearly has a map showing I-22 save the bit it is adding as part of the existing interstate system, per the
2012 request for establishment of I-22 along 96.22 miles of Future I-22 (which included the bit from 93 to I-65) that was conditionally approved pending MS submitting an application, and FHWA approval (as FHWA list 96.22 miles of I-22 in AL, and
have it as part of the interstate system on the map then clearly FHWA approved it).
As for MS, then the
FHWA approved it as I-22, with a boiler plate "they can sign it as future until it is added to the interstate network" given to all the requests. The
request said the whole route met interstate standards. I-22 in MS was an interstate on paper from May 14th 2015: 710 days ago! GMSV shows that it clearly didn't take 101 weeks to sign it.
I cannot see how I-22 can be consider anything other than an official interstate all the way from Future I-269 (not yet open exit 12) to I-65.
These are Froggie's states, but his last log-in to these forums were in Feb. I've made
a pull request making the changes*, but it's up to Froggie (or us deciding Froggie is inactive) whether it should be pulled or chucked.
*almost entirely cosmetic - the new I-65/I-22 interchange added on both routes, and a shaping point on I-22 between 93 and I-65. I renamed and moved the files, tweaked the .csvs and relabeled (keeping alt label) 'Fut269' as '12' to fit in with the rest of the route better than I-269Fut would.
