It is one of the two primary build Alternatives for the UR, and was actually the slightly favored one in the 2005 DEIR because that was back in the "BRT fever" days. The state's taken no subsequent action on the UR, so the '05 DEIR is still the most up-to-date corridor document. You can't make assumptions of final-pick mode choices until they dust it off for a modern look. As of today we're still frozen-in-time at the DEIR with both options in-play. So the Mountfort hillside has an incumbent project conflict on the books for doodling ramps setups. Any which way that conflict doesn't get resolved until something UR-related gets a second look.Who's going to advocate for reserving that for BRT? Doesn't seem like it would be freeway drivers who might want new ramps, or people who want to open up the waterfront, or most of the transit advocates who probably would prefer LRT.
Well, you don't know that unless it's buildable. Right now the Mountfort hillside isn't going to be under consideration for as long as the Urban Ring is in a deep-freeze, so plotting umpteen steps ahead to other speculative EB ramps and what services you're going to run on them isn't realistic speculation. Have to solve the logjam that opens *any* of these ramps up for consideration first before you can draw 2D BRT routes on a map. I would also caution that Pike Expresses are probably not going to be a big mode share once Riverside-turning Urban Rail service on the Worcester Line starts running. Most of the existing 5xx routes are going to immedately go away except for maybe a residual route re-draw or two that scratches some itch the B&A spine doesn't. Much of what your speculative offramp-hopping BRT route serves is going to get a crack at Boston Landing, West, Lansdowne, and Back Bay every 15 minutes on the train schedule with less iffy OTP than the bus in Interstate traffic. Of all the things driving the need for offramps transit is barely going to rate on the list after the 5xx's get their audience majority-subsumed by the Urban Rail schedules.And St Marys St freeway ramps have BRT potential in the form of Kenmore Sq Logan Express, if the Newbury St I-90 westbound on ramp just to the west of Mass Ave was moved far enough west that traffic using it would still merge onto the I-90 mainline before crossing the Muddy River, but making room for a new off ramp between Mass Ave and that newly relocated on ramp. The bus would exit the freeway just after Mass Ave, stop at Kenmore, then get back on the freeway eastbound at the St Marys St on ramp to go to Logan.
Finally...St. Mary's??? Ick. That is an absolutely terrible side street for trying to take on any high-capacity volumes, being a one-way and de facto pedestrian plaza in front of the BU Photonics building. I could see if it were a direct ramp onto Mountfort and then traffic gets picked off piecemeal on each successive block, but Town of Brookline and BU are going to take a hard pass at dumping out on one of their side streets. Honestly, there are limits to squeezing blood from stone here. Pickings are limited on what can geometrically be reached on the grid coming out of the Comm Ave. underpass, so if the only physical way to direct-access here is to throw an absolute dumpster fire of an exit queue onto St. Mary's...just stop. Doing literally nothing is better than the damage that would cause. Keeping Soldiers Field Rd. EB as strictly a long Kenmore connector is hands-down better traffic flow than making exiters bang multiple turns around the block from a side street choked with pedestrians.
I don't geometrically see how this is possible. You've got a solid wall of building massing on Comm Ave. starting at the BU Fine Arts building, a tight riverbank where the curvature of a loop ramp would be bugfuck tight, and an only realistic insertion point for a ramp mere couple dozen feet from the BU Bridge intersection meaning it takes crazy cross-cutting and uey-throwing to get on it in the first place. Same with St. Mary's queue dump...if it makes bad traffic at this busy intersection way, way worse because the only possible geometric exit design is bad geometry....it's not blood the least worth it to try to squeezing from that stone. Leave alone and just move on. When Beacon Park's street grid is infilled (hopefully before the heat death of the universe), there'll be an additional spanning street up in the Babcock area breaking up the currently 2-mile distance between Charlesgate and Harvard Ave. for getting across the Pike. Plus the post-straightening Allston exit being staggered across frontages that can distribute it to spanning streets. So the access problem is not going to be the same as present-day with the new options to get across to the foot of the Allston interchange from BU West. You still need Soldiers Field Rd.'s asynchronous EB load-bearing to reach Kenmore, but even that necessary remainder is not going to be quite so traffic-brittle in the future as it is today with the new grid options infilled around BP.For I-90 westbound, we might want to build an on ramp and off ramp just to the west of the BU Bridge which would connect to a one lane in each direction road that would go under the BU Bridge exactly where eastbound Storrow/SFR currently does, and connect to University Rd. We probably could build a flyover ramp west of the BU Bridge to feed into that as an eastbound I-90 to University Rd off ramp as well, although I think a potential major concern with this is that we probably don't want University Rd overwhelmed with high speed traffic. (Maybe 10' lanes on University Rd and a 20 MPH posted speed limit would help if we don't let freeway engineers redesign University Rd to be as freeway like as possible?) And a University Rd to I-90 westbound on ramp keeps traffic out of the heart of the BU Bridge / Commonwealth Ave intersection, whereas any off ramps feeding into there have potential to bring too much traffic to an intersection that may already be strained.