For years, the incomplete Hawaii Interstates were still designated as Interstates. Why are the freeway sections of the Glenn and Seward Highways around the Anchorage area not actually signed as Interstates A-1 and A-3 respectively? They are designated Interstate highways and even Google Maps identifies them as such.
Probably because the locals insist on calling them the Glenn and Seward Highways. They don't use the AK route designations, what makes anyone think they'd use the Interstate designations?
I assume the same as the other Scott. They likely refer to their highways by name -and I believe the numbers are really for logging and visual purposes. The A-X interstates are paper only. the only one really that could be signed - once they have it connected around Anchorage - is A-1. But the standards say one end must be on an interstate - which won't happen in our lifetime.
Those standards are for designating, not signing... ADOT&PF could run out tomorrow and post A-1 through A-3 if they wanted to even though it's not a freeway. Those interstates have already been officially designated, they are just unsigned.
It doesn't help that the Alaska Interstate numbers don't really synch with the existing state route numbers. The freeway part of A-3 is part of AK 1. The freeway part of A-4 is part of AK 3. Not that Alaskans care deeply about route numbers of any kind, but adding Interstate numbers would be confusing, if only to mapmakers and tourists.
When Alaska put in for AASHTO approval of its Interstate numberings circa 1980, it blew off AASHTO's helpful suggestion that A-3 be folded into A-1, so that the Interstate numbers could mostly synch with the state route numbers. Maybe Alaska DOT&PF was concerned that the freeway connnection between the Glenn and Seward highways would never be built (it's still in the planning stages, three decades later).
I think the Glenn and Seward freeway segments are probably close to conventional Interstate standards, but might not quite meet them. A bike trail running very close to part of the Glenn Highway is one thing that might require fixes before Interstate shields go up.