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Old 01-18-2018, 09:14 AM   #941
sm89
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Re: Silver Line to Chelsea

One of the snags with changing the signal at D is that there are closely spaced signals at D's intersections at Congress, Haul, and Summer. All of these are coordinated. There is some hesitation because of the impact that giving the busway more time has on the entire network of intersections.

I know the departments (BTD, MBTA, MassDOT?) meet at least monthly to discuss TSP and they have plans to implement them (in "places"), but I do not know why it has taken years to make changes.

If the D Street signal operated in isolation then this would be very straightforward.
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Old 01-18-2018, 09:17 AM   #942
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Re: Silver Line to Chelsea

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The MBTA is putting a lot of thought into that - I watched the FMCB livestream where Sec. Pollack was discussing a lot of details of battery bus procurement (not a mature technology, not enough vendors, lots of single-bus pilots but very few large procurements), though since it's not in any slides it would be far too much effort to find the video in the archive.
We really need to look outside the US for experience in this topic.

Every major city in China has huge battery electric bus fleets. We are buying Chinese train sets for the Red and Orange Lines, why not Chinese busses.

BYD has extensive experience in this area (battery electric busses). Shenzhen now has 14,000 (that is NOT a typo) electric buses, a 100% battery electric fleet, 80% supplied by BYD. The "not enough experience, not any large fleets" is a retrograde US canard (meaning BS).

https://cleantechnica.com/2017/11/12...lion-end-2017/
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Old 01-18-2018, 09:33 AM   #943
Joel N. Weber II
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Re: Silver Line to Chelsea

So Shenzhen has 10 times as many BYD battery powered buses as the MBTA has total buses?
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Old 01-18-2018, 09:38 AM   #944
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Re: Silver Line to Chelsea

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So Shenzhen has 10 times as many BYD battery powered buses as the MBTA has total buses?
Yes, exactly! And they started the changeover to all battery-electric about 7 years ago, so they also have operational experience.
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Old 01-18-2018, 09:42 AM   #945
Joel N. Weber II
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Re: Silver Line to Chelsea

Quote:
Originally Posted by sm89 View Post
One of the snags with changing the signal at D is that there are closely spaced signals at D's intersections at Congress, Haul, and Summer. All of these are coordinated. There is some hesitation because of the impact that giving the busway more time has on the entire network of intersections.
I seem to recall seeing a Longwood Ave traffic simulation video on Youtube by some folks at Northeastern discussing some potential changes to facilitate bicycling; would it be possible to get a similar video showing D Street with coordination and without coordination demonstrating what the biggest problems with dropping coordination would be?

Also, is there any clear evidence that person minutes of delay at the intersections in this area would get worse dropping coordination in favor of reducing bus waits?
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Old 01-18-2018, 11:32 AM   #946
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Re: Silver Line to Chelsea

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Also, is there any clear evidence that person minutes of delay at the intersections in this area would get worse dropping coordination in favor of reducing bus waits?
Vehicle delay appears to be the only factor for the current pols. It "looks bad" to have traffic, even if more "people" are getting around faster with it.
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Old 01-18-2018, 04:38 PM   #947
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Re: Silver Line to Chelsea

D St seems very simple to me. Rest in green/walk for D St. As a bus is detected as approaching from either direction, signal begins the countdown/FDW phase, then turns yellow and red for cars on D St. As bus reaches the intersection, signal turns green for buses. As soon as the last bus is through, signal changes back to D St green/walk. Set a minimum green for D St if you'd like, say 20 seconds, where the Silver Line couldn't trigger it again for at least 20 seconds, but I honestly don't think this is needed.
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Old 01-18-2018, 06:37 PM   #948
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Re: Silver Line to Chelsea

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Yes, exactly! And they started the changeover to all battery-electric about 7 years ago, so they also have operational experience.
Climate.

Their climate is far warmer than ours. The biggest issue I see with the Proterra buses is it's no bueno in cold weather.

Sure it can be done but the technology isn't quite there yet for us.
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Old 01-18-2018, 10:16 PM   #949
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Re: Silver Line to Chelsea

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D St seems very simple to me. Rest in green/walk for D St. As a bus is detected as approaching from either direction, signal begins the countdown/FDW phase, then turns yellow and red for cars on D St. As bus reaches the intersection, signal turns green for buses. As soon as the last bus is through, signal changes back to D St green/walk. Set a minimum green for D St if you'd like, say 20 seconds, where the Silver Line couldn't trigger it again for at least 20 seconds, but I honestly don't think this is needed.
Pretty much this. The pedestrian phase would force most of a 20 second minimum anyways. It will throw it totally out of coordination with the adjacent signals, but... priorities.
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Old 01-19-2018, 08:34 AM   #950
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Re: Silver Line to Chelsea

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D St seems very simple to me. Rest in green/walk for D St. As a bus is detected as approaching from either direction, signal begins the countdown/FDW phase, then turns yellow and red for cars on D St. As bus reaches the intersection, signal turns green for buses. As soon as the last bus is through, signal changes back to D St green/walk. Set a minimum green for D St if you'd like, say 20 seconds, where the Silver Line couldn't trigger it again for at least 20 seconds, but I honestly don't think this is needed.
If it was an isolated signal, yes, but D St/transitway is coordinated with at least 3 nearby intersections. Summer and Congress have multiple phases that they need to go through before transitway can be green, it's not just the ped clearance time that's holding them up.
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Old 01-19-2018, 09:01 AM   #951
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Re: Silver Line to Chelsea

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If it was an isolated signal, yes, but D St/transitway is coordinated with at least 3 nearby intersections. Summer and Congress have multiple phases that they need to go through before transitway can be green, it's not just the ped clearance time that's holding them up.
No, it's not a need, it's a choice to prioritize the movement of single occupant vehicles over 400 people waiting in the buses
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Old 01-19-2018, 09:29 AM   #952
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Re: Silver Line to Chelsea

^ Well, sorta. I definitely agree with the sentiment. But given the proximity there really is a (short-duration) gridlock risk if the transitway light is red and the feeding movements are green.
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Old 01-19-2018, 09:34 AM   #953
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Re: Silver Line to Chelsea

What if we just closed that section of D St? Honest question, what would be the ramifications?
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Old 01-19-2018, 05:59 PM   #954
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Re: Silver Line to Chelsea

How do you get to the Pike westbound from Northern Ave/Seaport Blvd if D street there is closed?

Gridlock risk is what I see as well without coordination.
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Old 01-19-2018, 08:38 PM   #955
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Re: Silver Line to Chelsea

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^ Well, sorta. I definitely agree with the sentiment. But given the proximity there really is a (short-duration) gridlock risk if the transitway light is red and the feeding movements are green.
Not much of a risk with Summer Street. Just need to shut off the D Street southbound @ Congress Street light to avoid gridlocking that intersection (hold the queues on the previous block).
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Old 01-19-2018, 10:13 PM   #956
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Re: Silver Line to Chelsea

Yeah congress is where the problem would be
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Old 01-19-2018, 11:04 PM   #957
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Re: Silver Line to Chelsea

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Originally Posted by cybah View Post
Climate.

Their climate is far warmer than ours. The biggest issue I see with the Proterra buses is it's no bueno in cold weather.

Sure it can be done but the technology isn't quite there yet for us.
Harbin is far colder than Boston, and they have cold weather electric buses.
http://www.chinabuses.org/2017/buses_0227/10890.html
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Old 01-20-2018, 07:29 AM   #958
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Re: Silver Line to Chelsea

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Originally Posted by cybah View Post
Climate.

Their climate is far warmer than ours. The biggest issue I see with the Proterra buses is it's no bueno in cold weather.

Sure it can be done but the technology isn't quite there yet for us.
For Shenzhen, sure. But Beijing, which has virtually the same temperature profile as Boston, has over 1,000 battery electric buses, and rapidly expanding (projected to be 10,000 in 2020). Qingdao, in China's northern coast (very similar to Boston in a northern coastal location) has over 800 battery electric buses in their fleet. They are in the process of receiving 1,000 more from BYD (BYD has a factory there). One way they deal with northern climate is battery swap-out and off-board charging, which appears pretty well perfected.

Argument does not hold up. China is moving much faster at perfecting battery-electric technology than we are at learning about what they are doing.
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Last edited by JeffDowntown; 01-20-2018 at 09:10 AM.
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Old 01-20-2018, 10:20 AM   #959
Joel N. Weber II
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Re: Silver Line to Chelsea

I think it would be totally reasonable for our first batch of 200 battery buses to figure out what range would be sufficient on what we think is our worst case coldest day for the routes covered by the 300-350 of our buses (half the buses used during the weekday peak) that are less demanding, and order buses that we think should be sufficient for that (including a margin of at least 10% vs the batteries when new; apparently Tesla batteries lose a few percent of range or something in the first year and then degrade more slowly). If it turns out that things are a little more challenging than we thought, maybe we then avoid using those buses on the 100 of those 300-350 that turn out to be most challenging on the coldest days.

I'd also like to better understand this requirement that buses have to work in terrible winter weather. Did the T apply that standard to the new 60' buses it has bought within the last few years with regard to traction on snow? (Remember, traction on snow was a solved problem with the dual mode buses back in 2005. Is the T so incompetent that they can't even buy solutions to actual problems we actually have that were actually solved ten years ago?)
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Old 01-26-2018, 07:47 AM   #960
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Re: Silver Line to Chelsea

One of the first things to happen around the Eastern Ave stop is the redevelopment of the innes apartment complex:

http://www.chelsearecord.com/2018/01...e-development/

It would be great if retail is an element of the rebuild. With all of the airport workers coming through that stop, it would be great to have a place to grab a coffee or meal on the way through.
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