Using data to help the CTA fight bus bunching

A team of data geeks is using bus GPS and passenger count data to “simulate future demand at every stop in Chicago, and predict how well transit service is likely to perform under a particular schedule change.”

In a blog post on Data Science for Social Good, Juan-Pablo Velez and Andres Akle Carranza note that “the vast quantities of vehicle location and passenger count data can probably allow us to predict crowding along a route before it develops.

Bus service simulations – reflecting the natural variability in ridership and service – would allow the agency to forecast how adding or removing service on a route might affect its crowding levels. These statistical models could help CTA make proactive service decisions that anticipate changes in ridership and reduce crowding before it starts.

The team of geeks has been hard at work this summer analyzing the data and developing solutions. It’s part of the Eric and Wendy Schmidt Data Science for Social Good summer fellowship at the University of Chicago. They expect to have some answers very soon.

This is a true partnership with the CTA that hopefully will benefit all of us. I thank you in advance for your work.

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  • May as well use the statistics for something, even though someone claimed on WTTW from the highly secret CTA control center* that the bunching problem was under control. Obviously, the passenger loading data exist, as is probably the on time performance of each bus.

    *Generally accepted to be 120 N. Racine.

  • Your headline is incorrect. they're trying to minimize crowding (ie buses too full), not bunching. though the former would assist the latter

  • In reply to whateva:

    That is essentially addressed in the part in the linked post on "Gaps between buses," noting that certain buses get overcrowded, even if enough buses are running, including " Eventually, an on-time bus following behind it is catches up, creating a bunch."

    So, unless the finding is that there are too few buses on a route, the essential problem they are tackling is bus bunching, although the technical stuff past that in the post is beyond me.

  • All the data on earth won't help if the secret CTA control center won't use it.
    It's not a secret that they play ball games 81 times a year at Addison & Clark. But every day they do play a game, the Clark bus is a mess for hours afterwards, due to the large passenger load that is released from the ball park at once.
    The CTA has had 55 years since the streetcars left Clark to figure this out & just can't do it!
    Now I realize there's no set time for the game to end, so it would be expensive to line up a half dozen buses to wait for the end, but they do have the ability to reassign a couple buses for a single run from a different route.
    That's why I really miss the street corner supervisors as I saw them reassign buses several times when nothing had shown up for 30 minutes in the rush hour!

  • In reply to ScooterLibbby:

    The CSL book said that they had a supervisor sitting in Chicago Stadium waiting for the end of the Black Hawks game to call out the streetcars. Maybe CTA is afraid that its supervisor would load up on $7.75 Bud Lights.

    Which reminds me of another point--

    --Remember when CTA came out with a Press Release saying that crowding on buses had been reduced by 28%, and despite Kevin saying "You're just never satisfied, are you Jack," it turned out that the methodology was bogus. Either this new project proves my point, or the study is unnecessary.

    What can be deduced from Scooter's point is that even if these guys crush the numbers, the highly secret control center and planning department (which the RTA director now says should be merged into the RTA) will ignore the recommendations.

  • In reply to ScooterLibbby:

    This may be possible, but how many buses can you possibly reassign off another route until you remedy one problem by creating another. I've seen supervisors at Howard L pull buses off the 22 to fill in trips on the 97 or one of the Evanstons (201,205,206). Fixes the problem on a line with a bigger headway but virtually no riders (save for the 97 being the exception), but create a mess on the busy line (22).

    Seeing as the Cubs do cut an incentive to the CTA for the extra service, there should be motivation to supply at least some extra service on Clark street as well (at least north to Howard, Devon or wherever).

  • In reply to ctadriver99:

    Your last paragraph shows the distinction.

    [Leaving aside my contention that CTA buses should get out of Evanston...] Unlike rerouting buses to take care of temporary gaps in service, when the Cubs are playing their 81 home games can certainly be known to the planners, although maybe not when a game goes to 14 innings. Somebody is putting 19 United Center buses onto the street at a certain point.

  • Bus bunching is not under control. Crowding either. Apparently managing the issue is tougher than splitting the atom. If anything the problem is worse now than ever. I think it happens because the bus drivers have to pull up and talk to each other for team building sessions initiated by some puke with an M.B.A.

  • What about getting bus racing under control?

  • In reply to ibilldavis:

    I might go see it if it is at the Joliet Raceway, Sunday, Sunday....

    But remember a couple of years ago when CTA was paying red light camera fines out of its operating budget?

  • They need to take a big long look at the #22. It's getting to be a regular thing that I have to wait through 2 or 3 buses to get one that isn't packed on my way home from work. They run the articulated buses in the AM rush but have stopped doing so for the PM rush.

  • In reply to Cheryl:

    Is the #22 the primary victim of the Lincoln and 1## north lakefront route eliminations?

  • In reply to urbanleftbehind:

    You'd think they would have extra articulated buses to run with the route eliminations.

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    In reply to Cheryl:

    Especially with NP (the garage running the 22) housing 120-130 articulateds at this point.

  • For God's sake, man, solving bus bunching is really simple. Leave it to a government funded organization to make it complicated. When two buses are on each other's tail, the front bus only stops when passengers need to get off until they put _________ minutes of spacing between them. Done.

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