Should this concurrency be broken? It was pretty clear when I drove US 276 WB on Sunday that it is never concurrent with US 25 NB (and that US 25 SB is briefly concurrent with US 276 EB).
I do not think I mentioned this during the usasc review.
I do wonder how this compares to I-110/US 54 in Texas though it is definitely clear that US 25 SB and US 276 EB are concurrent.
Clinched: I-10 (NM), I-110 (TX),
...
*I am uncertain in my mind if US 54 is truly concurrent with I-110, but I think it is very briefly.
US 54 peels away from I-110 just north of the border, ending at Loop 375. (I went that way earlier this year, to make sure I had clinched US 54, and then headed west to clinch the recently-completed 375.) The split is where traffic bound for Mexico stays on I-110, with at least one U-turn opportunity before crossing the border. But north of that point, US 54 is concurrent with the rest of I-110.
Given that I-110 runs on separate carriageways from US 54, I would say they aren't. Or at least not southbound. Northbound, only the ramp for I-10 east diverges before they merge, so I could see an argument for that direction.