A Green Line extension from Union Square along the Minuteman ROW has sometimes seemed more fit-for-purpose for Arlington to me -- better match for the Newton-like density (though see below), and better able to interface with the surface environment with grade crossings. But, I think last time I/someone else looked, it seemed unclear that there was enough width to fit both an LRT ROW and a bike path. (Center-running lanes on Mass Ave are also interesting, but that would be a lot of traffic lights + intersections to negotiate.)
That being said, I think the density is not actually what it looks like at first glance. Below are some modified screenshots of
@Teban54's amazing
population density map, in which I've removed color from tracts that are less dense than the tracts around the Newton Highlands and Newton Centre stations (which I've colored gold); the green and increasingly darker blue tracts are more and increasingly dense. All screenshots at the same zoom and scale.
As we can see, Arlington is actually significantly denser than the Green Line's sections of Newton. It is more comparable to Watertown and the north-of-Pike Newton neighborhoods, and not far off from Roslindale/West Roxbury. And the southern half of Arlington is basically on par with Quincy. Now, I'm not saying that such density
demands heavy rail, but I do think it's worth highlighting.
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Last summer,
@ritchiew raised the idea of extending to Arlington via Mass Ave (potentially bypassing Alewife), and I think the justification holds:
A Red Line extension to Arlington Heights should include a stop at Lake Street and Mass Ave. Call it East Arlington Station. That point is in the middle of the most population dense part of Arlington, and would be about a mile from Davis, Alewife, or Arlington Center. This would require not following the Minuteman path, at least for the portion south of AC. But not doing it would mean building rapid transit that goes a long way to skip over the densest part of town.
So first, this is the most population dense part of Arlington. Most of the town is single family homes, but this area isn’t. It’s all duplexes on small lots, plus some pockets of apartment buildings. To roughly quantify it, I was just looking at populations in census blocks within a quarter mile from different possible stations in Arlington. AH = 3589; AC = 3109; EA = 4792. That ordering holds true any way I can find to look at. And there are other draws to that intersection, like restaurants, shops, and a historic movie theater. It' small, but there's stuff there.
This becomes all-the-clearer when looking at the population density map above; Arlington south/east of Arlington Center is way denser than the north (comparable to Allston/Brighton) and is centered on Mass Ave, not the Minuteman.
If we're gonna need to tunnel (and all the more so if we're gonna need to use a TBM to avoid disrupting the surface -- whether Mass Ave or the Minuteman), then it seems worth tunneling to the places where more people live and where new subway stations will be more useful.
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Finally -- and I'm aware this is off-topic and represents a larger political gripe of mine -- from what I can tell, the Minuteman is estimated to have 2 million users per year. That comes out to an average of five or six thousand users per day. To put that number into context, that's around the same number of riders as at a single station like Braintree or Jackson Square or Fields Corner. It also happens to be less than the total ridership of the 77, which has roughly 7,000 daily riders.
The Minuteman is a beautiful linear park and obviously is valuable to its surrounding communities. But (temporarily) closing it for construction of a much higher capacity subway is not unreasonable.
