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A Toronto Researcher Wants to Make Traffic Lights Smarter

A U of T academic has found a way of getting traffic lights to "talk" to one another.

Samah El-Tantawy, a University of Toronto postdoctoral fellow, has invented something she thinks could revolutionize the way vehicle traffic flows in cities. It’s called the Multi-Agent Reinforcement Learning for Integrated Network of Adaptive Traffic Signal Controllers, or MARLIN-ATSC for short.

The system isn’t in use yet, but it has been tested on a simulator with real data from Toronto’s busiest intersections. It “thinks” on its own, and takes into account oncoming traffic from multiple intersections, and from all directions. Traffic lights connected to MARLIN-ATSC are able to interact, sort of like members of a sports team. In theory, it’s a big improvement over the current system of managing traffic signals, which in most cases relies on simple timers and sensors.

MARLIN-ATSC, which El-Tantawy has been working on with experts and researchers from U of T since 2004, shows promise. In simulations, it’s able to reduce delays per vehicle at intersections by 40 per cent.

El-Tantawy’s supervisor, Professor Baher Abdulhai, is the director of the Toronto Intelligent Transportation Systems Centre and Testbed, a type of laboratory for traffic technology. He says, “In 2000, I started a simple proposition, a research question. Can traffic lights learn, or can machine-learning in general be used to control or manage traffic?”

Almost a decade later, El-Tantawy has shown him it can be done.

“She added to the dimension of how to make traffic lights independent, intelligent agents that can communicate with each other using game theory, where essentially agents or players negotiate. For a system to be able to discover that on its own, that’s the novelty here.”

Anything capable of speeding up the flow of traffic could be useful in Toronto, where road congestion is an ongoing source of commuter pain. According to the 2011 National Household Survey, daily commutes in Toronto average 32.8 minutes, which is longer than the average commute in any other Canadian city.

In Toronto, there are 1800 lights that operate on predetermined traffic patterns and 350 that rely on real data to determine timing. The latter type of light has been used for the past 20 years and is nearing the end of its useful life, according to Myles Currie, the director of the city’s traffic management centre.

Although the City is considering ways of improving the coordination of some of its traffic signals, there are currently no plans to implement MARLIN-ATSC on Toronto’s streets. Currie wouldn’t comment on El-Tantawy’s system, because it hasn’t been tested with real drivers and cars.

El-Tantawy says her system would not only improve traffic flow, but, in the long run, would also be less expensive for the City. She believes it would cost between $20,000 and $30,000 to install MARLIN-ATSC at an intersection, with additional expenses for installing the software and other components. Plus, the system doesn’t rely on a pricey communications network. Nor does it demand highly skilled operators or safety staff.

Currie says the City’s current systems cost between $125,000 and $150,000 to install. They also require extensive in-house training for Currie’s staff, which is made up mostly of traffic engineering graduates.

El-Tantawy says she’s in the process of negotiating with a partner in the traffic-control industry, in the hopes of bringing her system to market.

“We’re forming a start-up company with them and my supervisor,” she says. “Hopefully it works and we can have our first field testing and commercialize it from there.”


  • wklis

    If it costs gravy, then Toronto does not want it. (That’s because I’m not the mayor.)

    • nevilleross

      Try blaming the deluded sheeple that voted for him to stop the gravy in the first place.

  • tyrannosaurus_rek

    Is anyone researching how to make Toronto motorists smarter?

  • scottld

    Lets make ADVANCE GREENs part of this like every other city. Have to say driving in the US is a breeze compared to being stuck behind left turning cars here. Why advance greens are so few here escapes me but I suspect it is because from my dealings with them Transportation Services lives in the 1950′s.

  • tomwest

    Sadly, this is not a new idea. Most major cities in the UK use a centralised control for their traffic signals, which monitors traffic conditions and reacts accodingly.

    • wklis

      Toronto has had traffic signal computers for decades. The trouble is that it has not be upgraded for decades. Upgrading is gravy for some people.

  • HotDang

    Instead of this, we should optimize traffic lights for bicycles, as they do in Copenhagen.

    • tyrannosaurus_rek

      Why instead of? Why not both? Build bike-recognition into the learning system and it’ll accomplish both things.

  • Bradford Hamilton

    Hey Toronto, you might want to put cameras on your lights so you can track your crack smoking mayor!! We have cameras all over South Florida and our mayors aren’t smoking crack.

    • dsmithhfx

      The mayor is under surveillance, the police can’t be bothered to make the arrest.

  • shuo
  • nevilleross

    Motherfracking Lords of Kobol, melodramatic much? This is just a new system that hasn’t even been implemented yet, and isn’t even in other cities yet? Also, how do you intend to convince taxpayers to pay for it all with taxes? Stop being such a whiny child who want the latest toy and just be glad that you don’t live in the Third World where you’ll have none of the things that are here in Canada.

  • wklis

    Pedestrians are getting less and less time to cross traffic signaled intersections than before. Just try to catch your bus at the opposite corners to where they are, and you could get ticketed.

    It used to be that people crossed on a green light. It still is in the driver’s handbook (where’s can I get a pedestrian’s handbook?) where it says that if there are no pedestrian signals, you can still cross on a green light.

    Then pedestrian signals came along, and in general we were able to WALK at the same time as the car’s green light. Then, in the interest of “safety” along came the flashing hand and the countdown. It became illegal for pedestrians to start their cross on the flashing hand or countdown. Pedestrian cannot legally cross, even
    if there was still a green light for cars, because it is “illegal” to do so. The pedestrian now had (legally speaking) less time to cross the intersection to catch their bus. Pedestrians can only start to cross if they see a still walking figure. And it is a very short time. Look around to grab your kids hands, and it’ll be too late (legally speaking) because there is a flashing stop hand.

    Worse, at many, many intersections, the pedestrian signals are almost always stop or don’t walk.