Comm Ave Bridge Replacement.

whittle said:
I remain unconvinced on capacity. Here's a good post by Ari on the capacity of BRT. Take particular note of the references to Metro Orange Line in LA since it would be a pretty good analogue to the type of BRT we could put on Comm Ave, and keep in mind that the Metro Orange Line has ridership well below that of of the B-Line.
Click to expand...

I get what the author is saying but I question whether the 12,000/hr metric is an effective way to measure efficiency. From what I'm reading, it's a metric to measure how many people can ride the LRT in a given hour which is most likely calculated from the number of trips per hour times the capacity of each train.

That's great an all but if it takes passengers over an hour to reach their destination when it should take 30 minutes, then capacity means nothing. A better metric is to measure the number of passengers transported to their destination bucketed into different trip duration (within 5 minutes, 10 minutes, 30 minutes, 45 minutes, 1 hr+) and then break it down into percentages. The distribution curve for a LRT like the B line would most likely be skewed towards the longer duration buckets (because of the train's slow speed) while the distribution curve for a BRT would probably be skewed towards the shorter duration and will remain there unless the BRT is unable to pick up everyone, at which point it will shift to the longer duration buckets.

And by the way, the analysis was done measuring the number of green line trains for all four lines. The capacity is significantly lower than the study when focusing on just the B line.
 
Last edited:
KentXie said:
And by the way, the analysis was done measuring the number of green line trains for all four lines. The capacity is significantly lower than the study when focusing on just the B line.
Click to expand...

Sort of (the typical LRT on the 3rd chart is a single branch of the B-Line), but regardless B-Line ridership still above what we could reasonably expect from Comm Ave BRT. Focus more on the limits of BRT. Metro Orange Line (which again is a good analogue for a hypothetical Comm Ave BRT since, while it has it has it's own corridor, it has numerous and frequent grade crossings) has 22500 daily passengers and peaks at 15 buses per hour. So we'd probably need ~25 buses per hour for the B-Line. Plus you'd probably want to work the 57 in through BU; it peaks at 12 buses per hour, but let's say we get that down to 8 with articulated buses. So we're looking at 30+ buses per hour which is well into the range where grade crossings would cause numerous issues.
 
They should be buttoning things up sometime this week & things should return to normal.
 
So my only gripe with this whole project is why the fuck is the green line running single car trains during rush hour at Babcock street? Once again, the MBTA has no idea what they are doing.
 
KentXie said:
So my only gripe with this whole project is why the fuck is the green line running single car trains during rush hour at Babcock street? Once again, the MBTA has no idea what they are doing.
Click to expand...

Kent, from the sounds of some of your posts, we share a similar commute. I have to agree with most/all of your sentiments about the B-branch: it is truly abysmal and unnecessarily bad. If you look at other aspects of the green line, things might not be ideal, but at least it's understandable why they are they way they are (e.g., limited capacity through the central subway in the city core...ROW crossings that would take large infrastructure changes to fix)...but with the B, it is just SO unnecessarily bad. I estimate it takes 5-7 minutes longer than it should to get from Washington St. to Kenmore. There are speed restrictions, lots of random stop signs along the route, and huge dwell times at numerous intersections...i get that TSP is going to help with some of this, but not all of it. And I get that some of the speed restrictions will be lifted when the rails are replaced...
But, I mean, there are certain aspects of it that make no logical sense...there's that stupid stop sign before Harvard ave that the train always gets stuck at so that 2-3 cars can cut off the train making that turn: 60 people have to wait so that 3 people can squeak by, really? Reroute/redesign the intersection...the larger # of people should get priority.

Seriously, if the T wants to stop bleeding ridership to other forms of transportation, they NEED to speed up the B. This thing is so neglected as of now.
 
Last edited:
"there's that stupid stop sign before Harvard ave that the train always gets stuck at so that 2-3 cars can cut off the train making that turn"

There used to be no stop signs for trains here but cars kept turning in front of trains (instead of yielding to them) and being hit. So the T's brilliant solution was to make the trains stop. (facepalm)
 
cden4 said:
"there's that stupid stop sign before Harvard ave that the train always gets stuck at so that 2-3 cars can cut off the train making that turn"

There used to be no stop signs for trains here but cars kept turning in front of trains (instead of yielding to them) and being hit. So the T's brilliant solution was to make the trains stop. (facepalm)
Click to expand...

Not sure if you are being sarcastic at me or at the T's move. I am 100% for "safety first," but this was the lazy solution. There are plenty of cities across Europe where the trams cross the auto lanes and they have various other ways of dealing with it that prioritize the mass transit. Rapid crossing gates, for one, could work. Or, eliminate that particular car turn, and reroute the traffic flow. Yes, I get it, they threw up all these stop signs for a good reason...but that doesn't make it a good design. Good design costs money, and lazy design is quick/cheap but carries with it a "we've-already-dealt-with-this" inertia...complacency sets in, etc.
 
Oh I totally agree. The stop sign for the trains was the lazy solution. The City of Boston would have (gasp) had to make changes to the road to make it safer for the trains, but clearly had no interest, so the T threw up some stop signs and called it a day.
 
cden4 said:
Oh I totally agree. The stop sign for the trains was the lazy solution. The City of Boston would have (gasp) had to make changes to the road to make it safer for the trains, but clearly had no interest, so the T threw up some stop signs and called it a day.
Click to expand...

There are also stop signs for the Green Line on Huntington Ave at Longwood Ave, EVEN THOUGH THERE ARE TROLLEY SIGNALS.
 
The MBTA, city, and state need to realize that they should expect more and more people to opt to drive / Uber /Lyft if the speed of public transit is abysmally slow. Because even pro-transit people like me...who desperately want to try to stay off the road...are going to cave and hail an Uber every now and then after a long/exahusting work day, when it's late, and I know that I live 3 miles away and can get there in an Uber in 20 minutes yet to take transit will take me 48 minutes. It'd be one thing if it were a 30 mile trip, and car or transit both took ~30 minutes. But it's a 3 mile trip...

Sure, during peak rush hour, the difference is smaller, and makes transit more attractive. But they need to be concerned with several hours +/- on either side of rush hour if they want to keep ridership up and therefore boost their revenues to provide the cashflow to sustain the system.

This is seriously going to be a big issue as the city faces transit policy now/near future.

I get it: all these little things on the Green Line, independently, are small. A stop sign here, a speed reduction there, a long dwell time at an intersection...and each one adds ~20-40 seconds...and, so, if you run the cost/benefit analysis without being sufficiently holistic about it, it's going to look like a huge infrastructural expense doesn't buy you much. But these T-rides are like death by a thousand cuts. Taken holistically, these little issues do add up to 10+ minutes per trip...and it's that sort of thing that pushes people away from transit.
 
Word is out now that the MBTA may be using part of the bridge for the extension of the newly revised long station platforms that it plans to build on parts of Comm Ave. Traffic shouldn't be affected, even though Green Line B service will be shut down & replaced by shuttle bus service. :(
 
Full-sized Type-10 double trains will fit on 225ft platforms. The nearest stops in each direction are 500ft +
 
We still have yet to find out what style they'll go with. I'm dying to know. :)
 
You must log in or register to reply here.

Back
Top