The Fresh Pond rotaries aren't bad at all for queue management. They got successfully rebuilt for much better law-and-order only 15 years ago. The pedestrian signals spread all around are quick and painless, Cambridge's much more recent re-striping of Concord Ave. out to the Belmont town line really cleaned that area up and made the Wheeler Ct. developments more easily accessible for left-turns without getting stuck, the other side of Concord Ave. was traffic-calmed with curb juts a decade ago, the bike access is all-around superlative, and those are some of the safest ped crossings you'll ever find on roads with those kinds of volumes.
It is high-traffic, and those rotaries do back-up. But it's orderly, drivers obey the yields, they obey the ped signals, and there's little-to-no lane cheating. So it flushes cleanly. You'll never sit there at a total dead stop for minutes on end. It can usually even flush itself entirely in one ped signal cycle (and there are a LOT of pedestrians punching those buttons). Those are all the outward signs of
good road design. It's not the full-speed running capacity, it's the recovery time when overtopped by circumstances outside of control and the rotaries' ability to keep near-constant flow under overload that make them well-designed.
Whoever shit all over that CTPS report seems to think that the only measure of a good road design is maximum speed limit, and that these rotaries are somehow brittle because you can't barrel through them at 45 MPH continuous all hours of the day. When that's the one and only design standard cro-magnon traffic engineers will consider, nothing helpful gets considered and you end up getting acutely counterproductive designs like "Brownsberger Square" just throwing more lanes and lane-cheating into the same vat of shit. The Concord Ave. duo are well-designed rotaries because you can overload them with an acute wave and they quickly recover. It either takes an accident, locking the entire hill to Alewife on 16E, or locking the entire hill to Huron on 16W to hose 'em. And those are not conditions related to the rotaries themselves. Not even the neverending sewer construction project that's tearing the crap out of North Cambridge with shifting detours and the the 2 years late the Concord Ave. reconstruction to Belmont has put any noticeable additional stress on the rotaries.
If they were worried about the rotaries in the CTPS study, they'd be doing these things first instead of burying it, coming back with "Brownsberger Square", and wondering why the locals violently reject that.
1) Do the Cambridge Park Dr./Rindge realignment. Because when they say they fear "Fresh Pond" backing up, they mean the hills on either side of Rindge. Yeah...damn right the hills back up! I wonder what's
right at the base of them that might be causing that?
2) Tweak the 16 @ Huron Ave. signal if they're concerned about the resiliency of the other side of the Concord Ave. rotaries. 16W does back up frequently from the Huron intersection to Cambridge Honda when there's more than one car in the left lane signaling for a left turn onto Huron. There's no left-turn lane or protected left there, so first sight of a flashing blinker when cars are rounding the curve up that hill gets everybody gunning for position to pass in the right lane with a slow-speed weaving mess. That gets worse when the largely unfixable Brattle and Mt. Auburn intersections are backed up further downwind. 16W needs a protected left onto Huron at the top of the hill, so 3 out of 4 directions (excepting geometry-constrained Fresh Pond NB) have a protected-left cycle. There's plenty of room with the little grassy knoll at the top of the hill to widen it out. There isn't even a sidewalk there to inconvenience walkers.
Also, since 16W deviates off-parkway around around the block Huron-to-Aberdeen to get onto Mt. Auburn for Watertown they might as well do a free-movement right traffic island at the top for the right that keeps to the signed state highway. Again, no sidewalk on that not-special grass patch for the next 2 blocks (should be, but that's city's problem), so no inconvenience if it's shaved to fit the protected-left lane and the free-movement right island.
No change whatsoever needed on low-volume Huron itself which has protected lefts both directions. No change whatsoever needed on the parkway down to Mt. Auburn which has unimprovable geometry. And total cost of not more than a few hundred grand to shave that grass patch and achieve the complete permanent fix for this intersection.
There...you fixed the hills bookending Rindge and fixed the hill at Huron. No potential whatsoever for a backup from Huron reaching within 2000 ft. of the second Concord Ave. rotary. And as previously outlined at length the station entrance/Cambridge Park Dr. realignment means no potential for a backup from the station or interchange going up the hill to the Mall and breaching the first Concord Ave. rotary. Both rotaries become irrelevant to the job at the 2 interchange, and any further bitching and moaning from MassDOT about the CTPS study becomes moot and baseless.
Why doesn't MassDOT want to do any of those straightforward fixes, and why do they want to intentionally concern-troll the rotaries to push their "Brownsberger Square" loser at the interchange? Because they're pouting at the notion of making parkway-grade infrastructure improvements with baked-in traffic calming and just want an excuse to build expressway-grade infrastructure. More lanes, more 50 MPH speed limits, a 1972 mentality forever...and who gives a fuck who gets stuck anywhere else because the naive little local yokels wanted "traffic calming".
Totally caustic attitude. But they may actually get chastened a little for it when they see how negative the reaction is going to be to the "Brownsberger Square" concept. They'll never ever revisit anything halfway-productive, but it might actually be better to kill that add-a-lane now and let anger fester and boil a few more years at this situation so a little more of this attitude gets beaten out of them by force and some officials who don't/won't get it have 'teachable moments' made at the expense of their careers (*cough*...Senator).
