The shortest "major" Interstates

[CobaltYoshi27]

Then I-81 could become the new I-85.

A significant portion of I-81 is also more east-west than north-south, particularly in Tennessee and Virginia.

Not nearly to the degree of I-85. Also I-26 seems more north-south to me. Maybe I-26 should be I-99, I-81 should be I-85, I-99 should be I-81, I-85 should be I-30, and I-30 should be I-26. Giant scramble.

[paulthemapguy]

I would like to see I-85 be renumbered as I-30 since it's more east-west than north-south.

Then I-81 could become the new I-85.

Then I-99 could become the new I-81.

Whoa.  Someone has my exact same idea.
And current I-30 would become I-32 or something.
(But I-83 would be off the grid in this case!  So I'd make it a northern extension of I-97.)

More importantly though, this thread's premise is my rationale for converting I-69 to I-45.  It's going to be a Canada-to-Mexico highway, so let's give it a number ending in 5!

[vdeane]

Then I-81 could become the new I-85.

A significant portion of I-81 is also more east-west than north-south, particularly in Tennessee and Virginia.

While only a portion of I-81 is east-west (the vast majority is north-south), the entirety of I-85 is east-west.

[Pink Jazz]

Perhaps to account for the east-west portion of I-81, I-85 could replace I-77 south of I-81 while replacing I-81 north/east of it, and the portion of I-81 between I-40 and the new I-85 can become I-54.  This would also eliminate the wrong-way I-77/I-81 concurrency.

[Zzonkmiles]

Perhaps to account for the east-west portion of I-81, I-85 could replace I-77 south of I-81 while replacing I-81 north/east of it, and the portion of I-81 between I-40 and the new I-85 can become I-54.  This would also eliminate the wrong-way I-77/I-81 concurrency.

I see two problems with this:

1. I-77 south of I-81 goes through Charlotte. The current I-85 also goes through Charlotte. This would require the old I-85 to be renumbered.

2. If the old I-85 got renumbered, having a new I-85 serve the exact same city, but with a totally different route (Statesville/Columbia instead of Greensboro/Spartanburg) would cause some massive confusion.

[empirestate]

Perhaps to account for the east-west portion of I-81, I-85 could replace I-77 south of I-81 while replacing I-81 north/east of it, and the portion of I-81 between I-40 and the new I-85 can become I-54.  This would also eliminate the wrong-way I-77/I-81 concurrency.

My idea for I-85 absolutely starts in Charleston (SC) and goes on to Columbia and Charlotte. Where it meets current I-81, I'm conflicted. Does it continue northerly to Charleston (WV) and thence on to Cleveland and/or Pittsburgh and Erie? Or does it take over the obviously prominent I-81 corridor, which goes through less-major cities, but reaches Canada and is more equidistant between I-75 and I-95?

(It's not totally unfair to suggest, if it does head to Pittsburgh/Erie, that it continue on to Buffalo and up to Niagara Falls and the border crossing there.)