The problem with highway-based BRT is that the ridership and usefulness will almost always be higher running on smaller roads through commercial centers. The MBTA's redesign isn't placing any bus routes on McGrath Highway, for instance.
Sure and for what it's worth any time I've heard politicians say that this would be a good corridor, I keep on wanting to give them a Fitchburg line timetable.
Pretty damn impractical given that it's already elevated through East Arlington and Belmont, with the cut section in the middle occurring on a steep grade. And deck-over for what? It's all single-family residential on half-acre plots as far as the eye can see. Trying for "density" in the middle would be totally incongruent with the surroundings and a great big dud on the market.
Outright deletion, at least on the scale l think you are referring to, is rare for multiple (and IMO legitimate) reasons, but at least in MA, it is not uncommon for projects to explicitly remove capacity. By far the biggest and best example is the Rt 79 project down in Fall River where DOT is removing 1.25 miles of a near-interstate standard, fully grade separated urban freeway to be replaced by a surface boulevard and developable land. I have *thoughts* about the execution, but undeniably, vehicular capacity and LOS in the commonwealth is already not the sacred cow it used to be.
The road diet being proposed for Rutherford Avenue in Charlestown is an example of this. And it is really hard to make happen.
I was a road design engineer for decades, and I saw how deeply the car-centric culture is embedded in the US psyche. It's damn near politically impossible to remove overpasses and underpasses, reduce lanes, and convert an expressway into a "complete street" type boulevard. Look at how intractable it is to remove the decayed and intrusive Bowker Overpass in Boston, how many years have gone by to even get to a 20% design to "ground" the McGrath Highway overpass, how preserving the underpasses along Rutherford Ave seems to keep popping up as an option in the endless iterations of plans for the project, how much opposition there is to bike lanes and bus lanes on certain existing major streets, and how hard it is to eliminate any on-street parking along those streets.
Maybe this is at a smaller scale than you're thinking, but Cambridge is repurposing a lot of car space for other uses. Mostly this is taking away on-street parking to make way for bike lanes, but also cafe space, especially around Central Square. You can see this along Mass Ave, Hampshire, Garden, Mt. Auburn, etc., with more streets planned for this spring. It almost seems normalized at this point that Cambridge will take away a lane of parked cars to use for other purposes. This is increasingly true in other cities around here, too.
110%, but it is now at least happening even if its at a rate well below where it should. 10 years ago l would have been laughed out of the room if l predicted DOT would wholesale remove an urban freeway without a building a functional replacement at least nearby. Progress is still way too slow (Rutherford Ave is probably the best poster child on that front), but l am optimistic because at least progress is happening and it is trending more and more in the right direction every day, even on major urban arterials.
Cambridge seems a bit more advanced than Boston in eliminating on-street parking for bike and/or bus lanes. Gotta brag a bit on my hometown!
Narrowing SFR to one lane each way won't buy much narrowing, as you'd still need a breakdown lane in addition to the one travel lane to get around disabled vehicles, adding up to pretty much the same width as two travel lanes. So, the only opportunity for narrowing the roadway footprint in the Throat area is to reduce the Mass Pike from 4 lanes to 3 lanes each way, but MassDOT seems to be against doing this.
Now THIS is the quality content that I come here for.
Filling in the throat shoreline just a few feet is a major lift (per the current preferred Mass Pike/SFR alternative) so I don't see how extensive filling there would ever be allowed politically. Certain powerful groups in Cambridge would be very unhappy with this. Even back in the early 1960s, filling in the Charles River enough to allow the Mass Pike to be built on the surface - instead of on the viaduct - was scuttled by Cambridge. I was there and remember it. And more recently the surface option for the Mass Pike through the throat area had to be cinched up as tight as possible to keep filling in the River to an absolute minimum.
I imagine that restricting lefts on the parts of Comm, Beacon, and Huntington with trolley reservations could speed up the B, C and E lines, respectively.