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Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 1:31 pm
by mulad
Didier wrote:This thread moves fast, so this might have been brought up already, but the University-Huron intersection is a total mess with the signaling. I ate an entire slice of Mesa pizza waiting for the eastbound light to turn green.
I bet that was sometimes possible before the train went in -- things got a lot worse through there when they rearranged the streets to accommodate TCF Stadium.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 1:44 pm
by Anondson
The biggest wild card on setting timings are the effect emergency responders have when they fly through prompting everything.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 1:47 pm
by David Greene
mulad wrote:Setting the pedestrian signals to always activate would make them more predictable rather than less (though it probably narrows the window of time that a train has to pass through an intersection or series of intersections).
That's what I meant by "unpredictable." With beg buttons you don't know when you'll need to insert the timing for a pedestrian phase. If it was just part of the regular cycle it would by definition be predictable. Maybe it already is, I haven't paid attention.

Holding a green for the train means you delay when that pedestrian slot activates (i.e. peds wait longer to cross, just like cares). I don't think pedestrian activity influences signal priority -- you're just holding the green, and thus the parallel pedestrian phase, a little longer. It's a problem for preemption because it limits when you can do the preemption. If the pedestrian signal always activates you always have that additional restriction on preemption so in that sense keeping the beg button does seem a little better.

Is there any island space for pedestrians to wait mid-block before and after crossing any tracks? If so, then peds should not be a factor for signaling. I think there would have to be space both before and after the tracks so that it completely isolates the pedestrian crossing from the tracks. So station areas might not even have enough there.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 1:48 pm
by David Greene
Anondson wrote:The biggest wild card on setting timings are the effect emergency responders have when they fly through prompting everything.
That's a very special case, though. I don't think anybody's saying the train needs to run exactly the same schedule in the presence of emergency vehicles. It should be possible to reset the timing pretty quickly.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 1:51 pm
by David Greene
nate wrote:It seems to me like the simplest system would be to equip the trains with signal-preemption devices that would only be used if it was running behind schedule. It isn't critical that the trains hit a green wave and fly through the line as fast as possible...it's that they stay on schedule and don't get bogged down stopping at streets like Mackubin.
I really like the idea of full preemption at secondary intersections. There's no reason at all cars there can't wait a few more seconds. Preemption at all intersections if the train is too far behind schedule is an interesting idea.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 1:54 pm
by HuskyGrad
Didier wrote:This thread moves fast, so this might have been brought up already, but the University-Huron intersection is a total mess with the signaling. I ate an entire slice of Mesa pizza waiting for the eastbound light to turn green.
I would presume the light did turn green, but there is a car that illegally entered the intersection sitting on the tracks.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 2:38 pm
by mulad
David Greene wrote:
Anondson wrote:The biggest wild card on setting timings are the effect emergency responders have when they fly through prompting everything.
That's a very special case, though. I don't think anybody's saying the train needs to run exactly the same schedule in the presence of emergency vehicles. It should be possible to reset the timing pretty quickly.
It's a special case, but it happens pretty often along the corridor. I shouldn't speculate on how often, so I'll just say I wish I had data on it.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 4:08 pm
by ProspectPete
I've noticed that emergency vehicles on university flip all 3 directions to red, with the exception of theirs. Also as fire trucks exit the stations they trigger signals to stop all traffic in both directions. There are 2 fire stations in St. Paul on university at vandalia and St. Albans.

Re: Green Line (Central Corridor LRT)

Posted: June 27th, 2014, 4:27 pm
by MinnMonkey
mulad wrote:I just sent a bunch of questions to Metro Transit's PR guy, with the hopes of publishing a response on streets.mn sometime in the next week.
Did you ever hear back from St. Paul? I have emailed a couple people last week and haven't heard a word back. I emailed MetroTransit and received a response within 2 hours.

Re: Green Line (Central Corridor LRT)

Posted: June 28th, 2014, 2:49 pm
by Minneapolisite
Was expecting to wait 15 minutes at Snelling since it was after 9PM, but the trains were running late so I only had to wait 10. It actually worked in my favor for once.

Re: Green Line (Central Corridor LRT)

Posted: June 28th, 2014, 4:03 pm
by mulad
MinnMonkey wrote:
mulad wrote:I just sent a bunch of questions to Metro Transit's PR guy, with the hopes of publishing a response on streets.mn sometime in the next week.
Did you ever hear back from St. Paul? I have emailed a couple people last week and haven't heard a word back. I emailed MetroTransit and received a response within 2 hours.
I haven't sent mail to anyone with the city yet, though I should. I got a brief response from Metro Transit after a few days saying they were forwarding it on, but I haven't had any questions answered yet.

I drove the stretch between 29th Ave in Minneapolis and Rice Street in Saint Paul four times this morning -- once with my normal driving speed (typically topping out around 33 mph on 30 mph streets) and again at a slower speed similar to what a train would be averaging (topping out around 23 mph). I took some GPS logs so I could see how many times I was stopped:
  • Normal westbound: 7 stoplights (also stopped once to be passed by an ambulance)
  • Normal eastbound: 7 stoplights (only really "stopped" at four -- for three, I only had to slow down)
  • Slow westbound: 11 stoplights
  • Slow eastbound: 15 stoplights
When I was driving slowly, there were also a bunch of lights that I made it through with just a short time to spare -- I wasn't paying attention to what the train's bar signals were doing, but they go to "yellow" (flashing vertical bar) and "red" (horizontal bar) earlier than car signals do, so a train would probably get stopped more than I was. I was also going at what the average speed of a train should be down the avenue, rather than aping their stops more closely.

Anyway, it's only a few data points, but I think this backs up the idea that the green wave for cars is causing trouble for trains.

Re: Green Line (Central Corridor LRT)

Posted: June 29th, 2014, 12:36 pm
by ProspectPete
I saw something encouraging today as I drove east on university: There was a train a about a block back following me, and as I approached one of those "secondary intersections" (Chatsworth I believe), where there was a car waiting to turn left. The LRT signal started flashing, and I thought to myself "what a bummer, the trains gonna have to stop for this one little car". But then the bar went solid again and the train continues on it's way. Is this an example of preemption evolving? I hadn't seen that before today, has anyone else? Maybe I just haven't seen it or been at the wrong place at the wrong time.

Re: Green Line (Central Corridor LRT)

Posted: June 29th, 2014, 2:12 pm
by nate
I saw that exact situation, on Griggs. A promising sign.

Re: Green Line (Central Corridor LRT)

Posted: June 29th, 2014, 10:42 pm
by Minnekid
I finally got to ride the Green Line today. It was okay, besides the fact that the ride time from end to end starting from Target Field Station took almost an hour and that trains were 10-15 minutes delayed because of some incident at Raymond Station I saw a lot of positives. On the Minneapolis end of the rail line it looked that besides one stop the ride was nonstop between stations because of efficient signal priority. But on the St Paul end there seemed the be consistent stops at red lights especially before the stops themselves. It would stop for 5-10 or even more seconds and then it would cross the street and stop once again at the stop itself. Not efficient at all. The way back from St. Paul the issues were the same and it stopped on the Minneapolis end of University but it was faster overall. It was like a 40 min ride.

Re: Green Line (Central Corridor LRT)

Posted: June 30th, 2014, 5:41 am
by David Greene
I experienced the same over the weekend. Eastbound from Fairview to Rice, the train stopped at every intersection in the middle of the stations, then again to stop at the station on the other side. Beyond frustrating. It was a 45 minute trip from Downtown East to Central.

I forgot to start the clock on the westbound return, but Dale to Hennepin was roughly the same time. I think the operator pulled the emergency brake at Lexington because we passed the eastbound station and then the train stopped really quickly in the middle of the intersection. I don't know if a car or ped tried to cross against the signal or if the train blew through the signal. That operator was fairly aggressive - quick acceleration and the train seemed to go faster westbound than eastbound but that could be perception because we didn't stop as much.

Re: Green Line (Central Corridor LRT)

Posted: June 30th, 2014, 9:27 am
by talindsay
I've taken perhaps ten roundtrips on the Green Line now and it's anecdotal because it's only a handful of random data points, but I clock every ride I take so I can say with certainty that on ALL the trips I've taken, without exception, westbound has been significantly faster than eastbound, between ten and fifteen percent. On Saturday I went Stadium Village to Rice in 31 minutes, and Rice to Stadium Village in 26. I can't imagine any reason why westbound would be faster than eastbound, and yet there it is - every trip, it's a three to five minute difference. I suppose the timing of my trips might mean some of the eastbounds have been at more busy times while all of the westbounds have been less busy, but I don't think that fully explains it. Can anybody corroborate or disprove this?

Re: Green Line (Central Corridor LRT)

Posted: June 30th, 2014, 9:53 am
by mulad
Anecdotally, I think I've had better luck getting a "green wave" when driving eastbound rather than westbound, which I suspect may have a stronger (negative) impact on the train. This could easily depend on the time of day, though.

My most recent trip to/from downtown Minneapolis was pretty slow westbound, but much better eastbound. I think there was congestion getting trains turned around at Target Field.

Re: Green Line (Central Corridor LRT)

Posted: June 30th, 2014, 4:41 pm
by MinnMonkey
Now if they can just get signal prioritization at Chicago and 4th. I have had several times where it took 5 minutes or more to get from 11th Ave to Downtown East station.

Re: Green Line (Central Corridor LRT)

Posted: June 30th, 2014, 8:06 pm
by nate
Some positive notes from my trip home this evening:

1) The "next train arrives in xx minutes" announcements were working, and they were accurate.
2) No red lights at all between Central and Marion. Only a 30 second pause at Marion, then no red lights until Lexington, again for a short pause. I didn't time the trip but I think it was 12 minutes or so. 3 minutes less than scheduled. Very convenient.
3) this was my 5th or 6th consecutive trip with minimal or no stops within the DT St Paul area, from the Rice station down to Central. It appears the timing on that segment is really getting figured out.

Re: Green Line (Central Corridor LRT)

Posted: June 30th, 2014, 8:33 pm
by MinnMonkey
nate wrote: 2) No red lights at all between Central and Marion. Only a 30 second pause at Marion, then no red lights until Lexington, again for a short pause. I didn't time the trip but I think it was 12 minutes or so. 3 minutes less than scheduled. Very convenient.
That is interesting. My trip from Raymond to downtown is often times 3 minutes shorter than the scheduled time until we hit the Green/Blue merge than we lose that lead.

If they can figure out something downtown Minneapolis, I think we could get close to the original 40 minutes end to end.