Is there any way US-1 could be designated I-193? For example, if they closed the 4th St exit and redesigned the MA-16 interchange, would it be compliant up to Copeland Circle?
Probably not because the thru route is still US 1. The feds probably aren't going to be keen on slapping a concurrency on it when the ultimate destination is the same exact route it's signed as today.
The only re-badging candidates in the state likely to pass with the feds (some higher odds than others) are:
-- I-93 relocated and displacing MA 3 to Sagamore Bridge and 3 getting deleted entirely (since it's a number violation conflicting with US 3).
-- I-x95 replacing Braintree-Canton I-93 in event necessitated by above 93 re-route.
-- I-293 relocating off the short NH 101 concurrency and displacing US 3 from Manchester south to 128 in Burlington. With US 3 displacing MA/NH 3A and expunging the northern suffixed route.
-- I-x95 replacing MA 24 when the substandard parts at the 93 interchange, between 495 and 140, at the deathtrap 79 interchange in Fall River, and at the 195 interchange in Westport get some basic upgrading. Feds probably won't approve it south of Fall River because of the disconnect between highway segments, very different destinations, and lack of compelling congestion or population density reason for it.
-- I-495 or I-195 absorbing the last of MA 25 to Bourne Bridge (might work better as 195 since east-west is the prevailing direction for Bourne Bridge traffic). Can only see this happening if the Southside Connector gets built between the Bourne Bridge and US 6.
-- I-195 displacing US 6 on the Cape IF it displaces MA 25 to the Bourne instead of 495 (has to be an east-west highway on the Mid-Cape Expressway), IF the Southside Connector gets built, IF 93 goes to the Sagamore, and IF the Mid-Cape gets widened from 2 to 4 lanes east of South Dennis. US 6 moves back to old routing expunging MA 6A.
-- Fixing the Auburn-Worcester I-395/I-290 confusion by picking one or the other (feds are the ones who screwed that up in 1983...MA/CT asked for 290 all the way to New London, and the feds surprised them by assigning 395 instead).
-- I-x90 replacing MA 146 if the last MA expressway gap in Sutton gets filled, and RIDOT fills the even shorter North Smithfield gap + upgrades some of the substandard expressway just south of 295.
-- I-x93 replacing the US 44 expressway IF the expressway is completed to 495 in Middleboro and IF 93 replaces MA 3 to the Sagamore. 44 moves back to its old route. Fits the mold if there's a pan-SE Mass highway designation effort to load-balance the Cape between the Bourne and Sagamore starting way far out, and for highlighting Plymouth as a major crossroads.