Here's a absolutely bonkers highway pitch, inspired by the fact that I was looking at the Tobin Approaches in Chelsea and wondering what manner of possibilities there are for solving the space constraints that resulted in a stacked highway structure in the first place - the cross section of the roadbed is notably narrow, requiring the CANA tunnels in Charlestown just to achieve the stacking. A tunnel along this alignment does make a lot of sense, but I can't see how it's actually constructable given that you'd also need to underpin the existing bridge / viaduct structures given that there's basically no spare width. The same applies to a replacement bridge - the existing Tobin is right up to its abutters. Given the minimal amounts of space, I couldn't see how any Tobin replacement could be built without either closing the Tobin/Rt1 completely for a decade or invasive eminent domaining. And I thought, if you're going to go megaproject and invasively eminent domain anyways...
Therefore, the Crazy Pitch: swap the alignments of Route 1 and Route 1A/60, leveraging the existing and fairly new Ted Williams Tunnel. (Let's assume it's capacity isn't already pretty maxed.) Here, I'm envisioning widening and grade separation of the 1A/60 alignment as a further extention of the Big Dig I-90 extention through Revere, meeting the existing Rt 1 at the Copeland Circle rotary. From the current I90 terminus, its already a 6 lane cross section. I'd close the Curtis /Addison access in favor of an underpasses, but Boardman/Winthrop would probably require access ramps, between which I'd propose a "backage" road, using this
disused MBTA RoW, which has minimal reuse potential, to provide site access to impacted properties. The few abutters on the Eastern side appear have reasonable access from local roads already, and from here simply take the Revere Beach Pkwy RoW, reconfiguring the interchange and expanding it with a new connection to the 1A alignment.
View attachment 60498
However, a maximialist approach (in red) which would remove the most highway from the most residents, is to continue along the rt 60 alignment. This next segment is maximally impactive to residential - I'd propose a modern elevated viaduct until we reach the Salem Turnpike Rotary, which by my count would affect <100 abutting residential properties, over 3 segments totaling about 0.75 miles. From here, we leave the existing alignment, and route along the rear arc of the commercial area, which skirts Rumney Marsh and which other than one new build apartment building is largely low value industrial uses, until you rejoin 1 at Copeland Circle.
This would, in theory, be a capacity "swap" that would allow you to take the Tobin out of service as a high level crossing, and rebuild this as a surface boulevard. From Charlestown, retaining the CANA tunnels as a connection to I-93, you can use the Chelsea St RoW and connect to New Rutherford. Plus, now that were accepting lights on this segment, we can build a surface level crossing with a moveable span across the Mystic, which can provide a long desired walkable/bikeable connection into Boston. A moveable span should provide adequate access to the Autoport and LNG terminal. Plus, with narrower lanes and no more viaduct supports, it should be possible to maintain at least a 4 lane cross section through Chelsea. In my estimation, it could in all likelihood include enough space to enable a transit reservation that could enable a Community College/North Station terminating LRT corridor in this important gap between Orange and Blue.
