Here’s How New CTA Technology Helps Reduce Bus Bunching

Demonstrating CTA's new bus bunching-fighting technology
Mike Haynes demonstrates sending an instructional message to a CTA bus driver using the new Bus Transit Management System.

If you ride Chicago Transit Authority buses, you’ve probably had the infuriating experience of waiting an eternity at a stop, only to have two or more buses show up at the same time. This phenomenon, known as bus bunching, is the bane of most big-city transit systems in the U.S.

To address this issue, the CTA is rolling out a new two-way bus communication system, and it’s already helping to reduce bunching on a handful of routes that have received the technology. The Bus Transit Management System, created by Clever Devices, the company that makes the CTA’s Bus Tracker system, pairs an on-board device with new software at the transit agency’s control center.

The software gives supervisors a heads-up when two buses are closer or further apart than they should be, and provides more information to help determine the best way to close the gap. If the supervisor wants more info from the bus driver – why they’re behind schedule, for example – at the next stop, he or she can send a series of text messages that require “yes” or “no” responses from the driver. The text messages appear on a device installed at the top left corner of the bus’ windshield.

Without the system, supervisors would continue having to drive around in their SUVs to see what’s happening and then intervene by catching up to a bus driver and giving them instructions.

At a demonstration of the system on Monday at the agency’s headquarters, CTA president Forrest Claypool said the technology is already making a difference in Chicago. Nine of the busiest South Side bus routes, based out of the 77th and 103rd Street garages, have seen a 40 percent reduction in “big gaps” between January and March. The agency defines big gaps as larger-than-scheduled periods of time between buses.

The new system gives supervisors several options for improving bus timing from the control center, according to CTA spokeswoman, Tammy Chase. The supervisor can order a driver to:

  • Hold the bus back by waiting at a stop
  • Run the bus express for a few stops
  • Leapfrog a leading bus
  • Temporarily follow a new route

“In some cases, an extra bus can be put into service to fill a big gap,” Chase said. “The software allows us to identify small issues before they become big ones.”

However, there’s a limit to how effective this technology can be for fighting delays on typical CTA routes that lack dedicated bus lanes and have stops every eighth of a mile. “As traffic rises, even small, random events like a double-parked car can cause buses to lose time,” DePaul transportation researcher Joseph Schwieterman told the Tribune. “That makes fixing the problem more difficult and it will test the limits of the technology.”

Demonstrating CTA's new bus bunching-fighting technology
Part of the BTMS includes monitoring headways, the time difference between buses. This screen shows in blue some late buses as well as alerts that some headways are not being abided.

Besides fighting bus bunching, BTMS is useful for a couple of other things. It allows control center staff to play prerecorded announcements on a bus’ public address system. For example, if a supervisor has heard reports of icy conditions at an upcoming stop, he or she can have the bus’ PA warn passengers to be careful as they disembark.

The system is also handy for locating items that passengers have left behind on buses. There was a real-life example of this on Tuesday. A customer who forgot her purse on a bus tweeted the CTA with the route and bus number, and supervisors used BTMS to ask the driver to look for the bag. Here’s how things turned out:

BTMS completely replaces the CTA’s 15-year-old, “outmoded and less functional” Bus Emergency Communications System, so it’s more than a simple technology upgrade, Chase said. The new, nearly $9 million system was funded by a federal grant. CTA is wrapping up the BTMS rollout and has already equipped over 80 percent of its bus fleet with the new tech.

  • Anne A

    “…if a supervisor has heard reports of icy conditions at an upcoming stop, he or she can have the bus’ PA warn passengers to be careful as they disembark.”

    During a snowy period in winter, that could be half of the stops on the 95W and many other south side routes. Perhaps it would make drivers more conscious of the need to slightly adjust their stop location if the normal bus stop is unwalkable.

  • After the data has had some time to build up this system will be great at identifying locations for service improvements. Preemptive signals, bus lanes, even intersection rebuilds could be justified using this data!

  • “As traffic rises, even small, random events like a double-parked car can cause buses to lose time,” Perhaps they can use the system to immediately inform operators of the obstruction and dispatch a tow truck to remove the offending vehicle?

  • BlueFairlane

    I’m skeptical that this program can fix the problem of bus bunching, in part because the options open to supervisors are so limited.

    You can’t really run a bus express, because people are inevitably going to want to get off at one of the stops you’re meant to pass. This means you either have to kick people off (which takes time) and make them wait for the next bus, or force them to pass their stop. And it’s not like rail where passing a couple of stops can gain you two miles, anyway.

    Buses leapfrog now, but the tactic is hampered by the fact that people want to get off where they want to get off. Leapfrogging buses are almost immediately caught by the buses they just passed.

    I can’t imagine the chaos that would ensue if you regularly diverted buses down alternate paths. People will be less likely to get on a bus if they’re not sure which route it’s going to follow.

    Which leaves holding a bus at the stop. So people who have waited some random amount of time for a bus to come get on that bus and keep waiting.

    Ultimately, I think we’d find most of these strategies more annoying than bunched buses, and I doubt they’d even do much to fix the problem.

  • Excellent point. All of our anecdotal data and our personal observations of how to improve things never get past this exact problem of no data to back it up.

  • So here’s my question to anyone in the know. Does the driver of the bus know that they are becoming bunched. In theory if a driver is behind or ahead of schedule they could assume that bunching is becoming a possibility. But if the buses in front and/or behind are experiencing the same issues with their schedule then no bunching is occurring.

    A bus that is getting too close to the bus behind could in theory skip on-boarding at the stops where no one is getting off.

    Is one of the current grails the giving of more information to the drivers about their relative position of their bus with the others? Clearly if a driver knows that they are creeping up on the next bus they could begin taking lots of simple slow down tactics. Especially if they are getting immediate feedback about the effects of their actions.

    Speed-up tactics are harder of course. But it seems that giving more information and autonomy to the drivers could help bunching.


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