Silver Line to Chelsea

sm89 said:
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.
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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?
 
Joel N. Weber II said:
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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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.
 
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.
 
JeffDowntown said:
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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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.
 
cden4 said:
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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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.
 
cden4 said:
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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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.
 
sm89 said:
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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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
 
^ 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.
 
What if we just closed that section of D St? Honest question, what would be the ramifications?
 
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.
 
CSTH said:
^ 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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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).
 
cybah said:
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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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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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?)
 
Joel N. Weber II said:
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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This requirement was not applied to the previous order of 60' buses because it would have lengthened the procurement process at a time when the T needed new buses fast (New Flyer would have had to redesign the XDE60 with a powered center axle). The T isn't being incompetent; there are no standard 60' buses that have powered center axles. The Neoplan DMAs are a completely customized model made specifically for the MBTA. New Flyer is designing the XE60 with a powered center axle; this will be the first mass-produced bus in North America with such a feature.
 
Didn't the T know about this problem when the 2008 60' buses were ordered, and know about how it was solved on the 2005 Neoplan dual mode buses?

If the T didn't communicate this issue to New Flyer when the 2008 buses were ordered or delivered and didn't make it clear that we needed a solution for the next batch to be ordered after the 2008 buses, then the T is incompetent.

If New Flyer learned about the problem by 2008 and how Neoplan had solved it in 2005 and New Flyer squandered several years they could have spent adapting the Neoplan solution to their buses such that they still didn't have a solution for the most recent batch, then New Flyer may not be competent enough to be expected to survive the transition to battery powered buses. (Isn't it possible for New Flyer to replicate the problem in their home town of Winnipeg, whose winter weather is not exactly tropical?)

One of the comments I've seen with the discussion of the recent agreement by Emirates to by more new A380s (even when the world doesn't seem to have a shortage of A380s that haven't necessarily reached their end of life) is that parts availability for something no longer in production is a concern.

If it's hard to be confident that New Flyer is going to survive the transition to battery buses, then buying New Flyer buses at this point may be risky in terms of parts availability over the next 12-15 years.

Much as I'd like all future T bus orders to not have internal combustion engines and rely entirely on batteries, I'm also wondering if there's any reason the battery system in the 2008' New Flyer 60' buses would not have been able to provide enough electricity to a center axle if they had installed an electric motor on the center axle.
 
Joel N. Weber II said:
Didn't the T know about this problem when the 2008 60' buses were ordered, and know about how it was solved on the 2005 Neoplan dual mode buses?
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The T received 155 D40LF buses in 2008. The DE60LFRs were delivered in 2010. And yes, the T knew about the traction issue with those buses.

Joel N. Weber II said:
If the T didn't communicate this issue to New Flyer when the 2008 buses were ordered or delivered and didn't make it clear that we needed a solution for the next batch to be ordered after the 2008 buses, then the T is incompetent.
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Despite buses being off-the-shelf products, the T still needs to go through a competitive bidding process to ensure that they're getting the best value for their money. There was no guarantee that New Flyer would produce the next batch of 60-foot buses for the T. Second, the market for 60-foot buses in North America is very small, let alone 60-foot hybrids. Why would New Flyer expend so much R&D resources on a feature or product that only a handful of cities would have an interest in? If the T required a powered center axle, then the cost of each bus would have more than doubled because the T would have had to pay for R&D costs. For only 25 buses that are supposed to last only 12 years and with a feature that would be used for less than 10 days per year, that's a proposition that I, as a taxpayer, would not be happy with.

Joel N. Weber II said:
If New Flyer learned about the problem by 2008 and how Neoplan had solved it in 2005 and New Flyer squandered several years they could have spent adapting the Neoplan solution to their buses such that they still didn't have a solution for the most recent batch, then New Flyer may not be competent enough to be expected to survive the transition to battery powered buses. (Isn't it possible for New Flyer to replicate the problem in their home town of Winnipeg, whose winter weather is not exactly tropical?)
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New Flyer is going to survive just fine. The 60-foot bus market is a niche; the 40-foot market is where the money is. You're complaining about a feature that would be useful for only small number of days per year and for a very small market segment.

Joel N. Weber II said:
Much as I'd like all future T bus orders to not have internal combustion engines and rely entirely on batteries, I'm also wondering if there's any reason the battery system in the 2008' New Flyer 60' buses would not have been able to provide enough electricity to a center axle if they had installed an electric motor on the center axle.
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The issue isn't with battery capacity; the Allison EP50 hybrid system is designed to propel only one axle, not two.
 
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