Speeding Up the Green Line

greenlinerankings1The Green Line’s on-time performance is poor. Few trains are able to meet the already relaxed running time. Lateness of 5 minutes is typical and 12 minutes not uncommon. After almost a month of late and erratically timed trains, it’s clear that unnecessarily restrictive traffic signals in St. Paul are the culprit. In contrast, Minneapolis is doing a pretty good job, with few delays because of their signals.

On top of the lateness, the slow running time is blowing a hole in Metro Transit’s budget, because more trains are required to keep the line from melting down due to the delays. We’re talking millions of additional dollars. The problem is the lack of full signal preemption at the low volume cross streets. There are simply too many traffic lights spaced too close together for conventional signal timing with priority to move the trains along.

St. Paul decided not to do full signal preemption because they didn’t want to unduly delay auto traffic crossing University Avenue. That concern is legitimate for the major streets—Rice, Marion, Dale, Lexington, Hamline, Snelling, Fairview and Vandalia. MnDOT’s online traffic volumes map shows that these have traffic volumes equal or greater than University.

However, there are 19 additional intersections where University has anywhere from 2 to 7 times the traffic of the cross street (see the table)University traffic volumes. Add the LRT riders and that difference increases to 3 to 8 times greater. Several of these cross streets have such low volumes that MnDOT and the City don’t even bother to do traffic counts, meaning they’re under 3000 cars per day.

At a lot of these intersections, a train with 200 passengers sits waiting for a handful of cars on the cross street to clear the intersection. The goal of not delaying autos has produced a perverse effect-more cars are delayed on University than on the cross streets-and it’s clearly hurting the Green Line at the same time.

So convert those low volume intersections to full preemption. That will greatly improve the Green Line’s on-time performance and reduce its operating expense.

Aaron Isaacs

About Aaron Isaacs

Aaron retired in 2006 after 33 years as a planner and manager for Metro Transit, where he worked in route and schedule planning, operations, maintenance, transit facilities, light rail and traffic advantages for buses. He created the bus-only shoulder and developed 270 miles of them, a national model. He worked on the Met Council's first TOD handbook. He's an historian of transit, as a 40+ year volunteer with the Minnesota Streetcar Museum. He's co-author of Twin Cities by Trolley, The Streetcar Era in Minneapolis and St. Paul, and author of Twin Ports by Trolley on Duluth-Superior.

30 thoughts on “Speeding Up the Green Line

  1. Froggie

    You could probably go one farther and even introduce at least some sort of partial pre-emption at Fairview and Vandalia.

    BTW, regarding your traffic count chart, I’m surprised you didn’t use 2011/2012 data (it’s available).

    1. Carson

      There are even more recent counts (2013) for University and some of the larger cross streets. Available through MnDOT’s Traffic Mapping App: http://mndotgis.dot.state.mn.us/tfa/Map

      It is viewable through the Draft AADT layer. Many volumes have changed considerably from 2008, which I imagine is attributable to Green Line Construction. Specifically, volumes have decreased on almost all segments of University.

  2. neb

    It also seems there are far too many left turns allowed as well. (for example, is there really a need for a left turn on to Grotto Street? Not to mention the safety risks that are present with this, it must slow the train down as you have to to provide the separate signal. Of course its too late to do anything about that, but would be good to revisit at some point and redesign.

  3. alienearthling

    the green line also has a deleterious effect on the blue line, as trains on that line sit at the cedar/riverside stop & wait for the green line to cross 94 into downtown.

  4. Walker AngellWalker Angell

    Glad to have you posting on here Aaron.

    Is part of this our seeming love of extremely long cycle times? Making a left from westbound University to southbound Western I’ll wait an average of about two minutes. Most of this two minutes is for an empty intersection with cars waiting from other directions. Occasionally a car on E or W University will go through but mid-morning this is not a busy place. About every other day a eastbound green line will be waiting for this empty intersection as well. I’d think we could reduce the overall cycle by half or more with no negative impact and much positive.

    I also can’t imagine that preemption here would be any sort of problem. The only people who’d be stopped by it are people who are already waiting on an empty intersection. I’d much rather wait on a train than nothing.

    1. JustAGuy

      The long delays at an empty intersection are common in Stadium Village as well, sometimes so long that it will back up on University and Huron past other intersections. But no train nor vehicles pass, just red lights for all for up to five minutes at a time (which, because of the amount of traffic backed up, takes quite a while and multiple light cycles to clear out).

      This seemed to be working well when they were running practice trains for two months prior to service.

  5. Monte Castleman

    That’s one thought I had- do we really need all those left turns and median openings? It’s handy to get to Ax-Man on Fry St, but not a whole lot of people seem to be using some of those minor streets.

    1. Joe

      Fry is the one street with more than 8,000 that should keep a full crossing, meant to have all auto-traffic from EB University to SB Snelling and NB Snelling to WB University, such as to lower volumes at Snelling and University intersection.

      1. neb

        you can still keep the full crossing open but eliminate the left hand turns from University on to Fry. That, and doing the same on several other intersections that are not significant would cut down need for additional signal phase for left hand turn, saving time. For those that want to turn left on to Fry, for example, one option for them is to loop around the block. I’m sure there will also be accidents involving left hand turning cars which could temporarily stop the train and impact travel times now and then.

  6. Nathan Roisennate

    Another thing to consider is that the train’s green phase is considerably shorter than the green phase for cars — it is not uncommon for the train to stop at a major intersection while the traffic light is still green for another 3-5 seconds. This causes the worst kind of delay, because it requires the train to wait for EB/WB traffic on University to turn left, then for the NB/SB traffic on the cross street to go straight, then the NB/SB traffic on the cross street to turn left. That’s a three-minute delay, easily.

    I suspect that if the train was able to extend the green phase slightly (as it is supposed to be able to do) at these intersections, then the 48 minute end-to-end time would be consistently achievable.

    Another problem I’ve noticed: If the train happens to make it through the lights at a major intersection without stopping, then its likelihood of making it through the lights at the next minor intersection are considerably lower. It seems the adjacent signals are not communicating with one another properly.

  7. Matty LangMatty Lang

    Thanks for writing Aaron. It’s very frustrating that the City of Saint Paul Public Works staff is refusing to change these obviously wrong-headed decisions to prioritize car traffic at such great expense. Becoming aware of the financial impacts to the Metro Transit budget makes this situation even worse. I hadn’t known that until reading your piece.

  8. Faith

    The downtown Minneapolis section still needs improvement, now more than ever. All WB trains stop at Marquette, no matter when they arrive (even though they could go at the same time as WB auto traffic which may get the next phase). After waiting through all phases (WB cars & N-S cars & buses), then the trains move forward one block to the station. With the addition of the Green Line, I’ve seen trains stack a few times now.

    There is also a ‘no go’ phase at Marquette with red lights for everyone and it is long enough to cross the street. The people who walk there often know this and start crossing when cars quit moving and there is no train present.

  9. MplsJaromir

    Great article, I appreciate well reasoned, clear and concise criticism. Judging by the message and prose I can tell comes from a well reasoned and well intended place.

  10. Katie

    Thank you for articulating what I, as a 2x daily Green Line rider, have been thinking from day 1. Are these concerns being heard by people in the position to actually make changes?

  11. Anna

    I’d encourage everyone who feels strongly about this issue to write a letter to their St. Paul City Council member. I know I will be. It’s such a shame that we aren’t prioritizing the billion dollars we spent on a train over a handful of single-occupancy cars.

  12. paddy

    Are you kidding me? Are.You. Kidding. Me? Now, now you care about how much money this project wastes. Bahaha. I’ll pass thanks. Build an elevated rail next if you care about times. Screw you and screw your choo-choo if you think your going to take a dump on my neighborhood by turning into a ghetto

    1. Jeff Klein

      What is it with transit-haters and “choo-choo” anyways? I’m forced to assume they’re toddlers.

  13. Aaron IsaacsAaron Isaacs Post author

    When I wrote the piece, I wanted to focus on the worst delays, which is why I didn’t mention some that appear in the comments above. After taking another ride yesterday, I should add that the lights on University are clearly timed for auto traffic, not LRT. Most of the stations are farside (meaning beyond the intersection). After stopping at the station, the trains always just missed getting a green at the next light, even though we were traveling 40-45 mph. We couldn’t catch up to the signal cycle. The obvious answer is to slow it down to match the LRT speed between intersections.
    Aaron

    1. Matty LangMatty Lang

      As a Saint Paul resident I have plenty of experience with the city engineering staff placing car traffic at the top of the priority list with a huge gap between number 1 and 2 on that list. I really thought that the Green Line would be different, but I guess that was naive of me to think that.

  14. herb

    Mayor Coleman and the city council need to be made aware of these concerns. This is a decision with significant regional impact which shouldnt be in the hands of unknown employees in City Engineering.
    There is no need for any of the left turn lanes at minor cross streets like Fry, Pascal, Grotto, etc.. Not only does it slow the train, but every left turn is a fatal accident waiting to happen when someone ignores the light and gets taken out by an LRT coming from behind them on the left, where they aren’t looking.

  15. Paul

    As a St Paul Green Line rider that used to take the 21A to Hiawatha, one of the biggest issues that I see together with the stated preemption issue is VERY inconsistent train operators. Many times between stops we are being passed by cars that are going the speed limit. I would say maybe 30% of the time the speeds are satisfactory, but at least 70% of the time the drivers are WAY too slow between stops. This comes down to training. Would it not be possible to transfer a few of the Blue Line operators to train them in on the Green Line route now that it is fully functional?

  16. Vince

    While it’s clear that St. Paul traffic signals are not properly timed and contribute to delays, there’s more wrong with Green Line operations than that. I was on a train last week that experienced a 9 minute delay between the Blue/Green line junction and the Downtown East station, with 3 of those minutes stopped at the traffic signal on Chicago Ave and 2 minutes stopped at 11th St. The delay on this short segment was even longer during the first 2 weeks of running. There are also problems between the two Target Field stations… delays there are 4-5 minutes, even though on the diagram both stations are listed as one stop. In those cases I could count 13-14 minutes of delay even before the trains left Minneapolis. It’s therefore clear that MTC has multiple problems to work out in order to get the trains to run on time. This is especially frustrating as it seems like something that could have easily been understood via computer modelling even before construction started.

  17. Pam martin

    How long do we wait for these timing issues to be fixed? It takes me twice as long to get to work by light rail vs driving. I am willing to put up with that for a while….but not forever. I anticipate them losing hundreds of paying riders over time. The bulk of passengers don’t pay and don’t have to be anywhere at any particular time.

  18. Jesse Langanki

    Instead of signal pre-emption at low-volume streets, how about getting rid of the signal entirely at low-volume streets? Make them all Right-turn only onto University and force cars to use one of a few major intersections to cross University.

    This would make University more like a “county road” with fewer crossing opportunities to slow everyone down.

    ALSO, the Green Line trains need Stop buttons/cords. If nobody pulls the cord, and nobody is waiting on the platform then it should fly through a stop at 40 MPH.

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  20. Nick Musachio

    Preemption is a great idea if you are happy with creating more auto congestion and emissions. I am proposing Always Green Traffic Control (AGTC). You can read about here:http://www.huffingtonpost.com/jennifer-grayson/innovation-earth-this-tec_b_5166878.html.

    AGTC informs light rail conductors of the optimum speed to go so that they will always hit the green light portion of the upcoming traffic light. It’s a win/win/win solution for the commuter, the light rail passenger and the environment. I’ve discussed it with David Levinson and he agrees that it would be wise to model this system, with further testing pending successful outcome of modeling.

    This system would also inform drivers and bicyclists of the precise speed to drive so as to make the next green light. In modeling it reduces queueing (BTW-the only English word with 5 vowels in a row) by 95% and thus also reduces emissions and saves fuel.

    Nick Musachio

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