Highways you're surprised it hasn't gotten truncated/decommissioned

[MATraveler128]

I-391 in Massachusetts - basically the Chicopee expressway.

I-195 in Maine: road to OOB.

I-189 in Vermont: (not even) Burlington bypass.

I-790 in NY: basically an overlay to NY-12

The only reason to keep I-790 around is so NYSDOT can use 90% NHP on its length.  And, I don't think anyone agrees on the exact begin and end of it...which works to NYSDOT's advantage.

Not sure why you think the others should be changed, though.

I agree with I-790 in Utica. Get rid of it and save it for something else.

Do bear in mind that I-189 in Vermont was initially supposed to be part of a longer route into Downtown Burlington, so it would have been more useful. VT 189 would be fine.

I-195 in Maine is indeed useful for summer traffic from Old Orchard Beach to get to the Maine Turnpike.

My vote would be I-393 in New Hampshire. It doesn’t really serve anywhere important.