General Infrastructure

[FK4]

There's your answer...

Sigh… I’d googled and found nothing and kind of amazed it seems as far as I can tell to have not even been discussed anywhere.

 

[Arenacale]

Interesting. I do like that they all include a left turn onto 93 north, because I feel like most ppl that enter the circle do so only to go around it and back to get onto 93 north, so if you give drivers the ability to just turn left onto the ramp that should drastically decrease the amount of people either going to the new intersection or rotary.

Because I always approached getting on the highway there from Southie and never Dorchester, I never noticed that you can't take a left from Columbia eastbound to get on 93N. I agree, that would be a major reduction in cars going to the rotary if they could pull it off.

 

[Scott]

I am surprised because one important benefit of a rotary is that you never have cross over traffic to take a left where it may be dangerous

 

[millerm277]

Anyone know if there are any movements afoot to put Revere Beach Parkway on a diet? It's always been such a ghastly road to me, and that third lane seems to unnecessary. It could actually be a pretty parkway if they eliminated both 3rd lanes and put in some trees, but I never hear any discussion on here about this particular DCR deathtrap.

Kind of? There's efforts going on to rework Wellington and Sweetser Circle - which are both pretty significant, but not a broader corridor thing.

While I don't drive the road that frequently, the core road issue to my eyes seems to be a few absolutely terrible intersections that crush throughput and distort the view of how much roadway capacity is needed.

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To pick the single worst example:

At present you need 3 lanes towards 2nd St not because there's 3 lanes worth of free-flowing traffic or that you should need 3 lanes to move that number of cars down the road, but because the intersection is so broken that you need them for literal car storage, as especially going EB it's frequently a 3/4mi long 3-lane wide queue that already backs up into Sweetser + further breaks it, and would likely gridlock all the way back through Santilli + towards Wellington if you cut it to 2.

You could almost certainly slash a lane off the entire stretch through there if you could find a way to make the 2nd St intersection less hopeless. Would have been better to work on before the Anthem building went up, but I do wonder if you could get the geometry improved meaningfully enough to improve anything with taking the auto body shop to the north.

 

[KCasiglio]

The MPO did a study a few years ago on the Everett/Chelsea section: https://www.ctps.org/data/pdf/studi...6-Chelsea-Everett-Priority-Corridor-Study.pdf

Improvement recommendations begin on page 96 - It does not appear that lane reduction was included.

 

[Koopzilla24]

Interesting. I do like that they all include a left turn onto 93 north, because I feel like most ppl that enter the circle do so only to go around it and back to get onto 93 north, so if you give drivers the ability to just turn left onto the ramp that should drastically decrease the amount of people either going to the new intersection or rotary.

This is the one and only thing I think we should emulate from Florida specifically for the Columbia/93 exit:

Minus the straight-through lanes because in our case they're ramps not frontage roads

Of course it'd be on a smaller scale and we can eliminate the slip lanes but consolidating all movements to a single signalized intersecting point would separate and streamline movements through the intersection. And since I-93 is on quite a sizeable viaduct here there's more than enough room to do this and it could be performed in conjunction with the inevitable replacement of the viaduct structure so that the current support structures underneath aren't in the way.

With this configuration there would only need to be 3 signal phases (different colored arrows) and pedestrians could have either a full independent phase or have different segments on a walk whilst there is no traffic green to cross them. Modern adaptive signals could shorten or lengthen phases based on traffic volumes for each movement, prioritizing the yellow phases to keep the rotary from backing up too much from having a signal so close to its branch.

Apologies for the amount of white space couldn't crop it in paint and Windows has some weird browser software that was being a pain

 

[real_EthanHunt]

another option to the Single Point Urban Interchange (shown above) is to do a diverting diamond interchange. its basically an SPUI but with the Columbia Rd approaches flipped so that all of the left turns (EB to NB on ramp, SB off ramp to EB, NB off ramp to WB, and WB to SB on ramp) dont have to cross traffic.
Of course, this being New England, peoples head would explode when they first saw it.

 

[ceo]

another option to the Single Point Urban Interchange (shown above) is to do a diverting diamond interchange. its basically an SPUI but with the Columbia Rd approaches flipped so that all of the left turns (EB to NB on ramp, SB off ramp to EB, NB off ramp to WB, and WB to SB on ramp) dont have to cross traffic.
Of course, this being New England, peoples head would explode when they first saw it.

One of the options presented in the, er, presentation is a diverging diamond under I-93. I'm a bigger fan of SPUIs for no particular reason; one of the problems with them is that the large paved area can make snow removal problematic, but presumably that's less of an issue under an overpass.

 

[ceo]

I am surprised because one important benefit of a rotary is that you never have cross over traffic to take a left where it may be dangerous

The existing rotary isn't under the highway, it's 100ish' to the east. I have to loop all the way around it regularly, coming back from Franklin Park Zoo, and being able to just turn left onto I-93 would be awesome.

 

[ceo]

Mass., Maine receive $11 million from wildlife crossing federal grants - The Boston Globe

Massachusetts and Maine have been selected as two of 16 states to receive a portion of $125 million in grants.

www.bostonglobe.com

Oh, that's interesting, they're planning to replace the existing Appalachian Trail bridge over the Pike with a combined trail and wildlife crossing. That'll require some clever design. From the grant statement:

The project will offer separate and distinct areas for wildlife, pedestrians and hikers and include fencing to help funnel wildlife to the crossings

I kind of doubt that they're going to design in separate trails for thru-hikers and regular pedestrians, but I suppose it's possible.

 

[millerm277]

Oh, that's interesting, they're planning to replace the existing Appalachian Trail bridge over the Pike with a combined trail and wildlife crossing. That'll require some clever design. From the grant statement:

I kind of doubt that they're going to design in separate trails for thru-hikers and regular pedestrians, but I suppose it's possible.

I assume that's just bad phrasing (or language that sounds better for federal grant criteria/scoring or something).

There aren't any "normal" pedestrians, the south side of the bridge only goes to a hiking trail/undeveloped land, you can't walk anywhere else - so you're a hiker of some kind if you are using it.

 

[Scott]

The existing rotary isn't under the highway, it's 100ish' to the east. I have to loop all the way around it regularly, coming back from Franklin Park Zoo, and being able to just turn left onto I-93 would be awesome.

I am from Dorchester, I know where it is, and it is not wrong to point out that part of the reason that a rotary was chosen way back when was to avoid having to take a left across traffic. Another reason was so that cars don't back up behind the car wanting to take a left. I was not objecting to potential changes, just surprised that a left turn would be added