SignalGuru uses network of dashboard-mounted smartphones to help drivers avoid red traffic lights

SignalGuru uses network of das...
SignalGuru uses visual data from a network of smartphone cameras to tell drivers the optimal speed to get a green light (Image: MIT/ Patrick Gillooly)
SignalGuru uses visual data from a network of smartphone cameras to tell drivers the optimal speed to get a green light (Image: MIT/ Patrick Gillooly)
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SignalGuru service screenshot (Image: Koukoumidis, Peh & Martonosi)
SignalGuru service screenshot (Image: Koukoumidis, Peh & Martonosi)
SignalGuru uses visual data from a network of smartphone cameras to tell drivers the optimal speed to get a green light (Image: MIT/ Patrick Gillooly)
SignalGuru uses visual data from a network of smartphone cameras to tell drivers the optimal speed to get a green light (Image: MIT/ Patrick Gillooly)

The continuing increase in gasoline prices around the world over the past decade has also seen an increase in the practice of hypermiling - the act of driving using techniques that maximize fuel economy. One of the most effective hypermiling techniques is maintaining a steady speed while driving instead of constantly stopping and starting. Unfortunately, traffic lights all too often conspire to foil attempts at keeping the vehicle rolling. Researchers at MIT and Princeton have now devised a system that gathers visual data from the cameras of a network of dashboard-mounted smartphones and tells drivers the optimal speed to drive at to avoid waiting at the next set of lights.

The new system, dubbed SignalGuru, was tested in both Cambridge, Massachusetts, and in Singapore. In Cambridge, where traffic signals are on fixed schedules, the researchers say the system was able to predict when lights would change with an average error of only two-thirds of a second and helped drivers cut fuel consumption by an average of 20 percent. In Singapore, where the duration of lights varies continuously according to changes in traffic flow, the error increased to an average of slightly more than one second, with one particularly light in densely populated central Singapore seeing an average error of more than two seconds.

The version of the system used in the tests graphically displayed the optimal speed for avoiding a full stop at the next light, but a commercial version would probably use audio prompts said Emmanouil Koukoumidis, a visiting researcher at MIT who led the project. The researchers also modeled the effect of instructing drivers to accelerate in order to catch lights before they changed, but decided that wasn't the safest option.

SignalGuru service screenshot (Image: Koukoumidis, Peh & Martonosi)
SignalGuru service screenshot (Image: Koukoumidis, Peh & Martonosi)

"The good news for the U.S. is that most signals in the U.S. are dummy signals," (signals with fixed schedules), says Koukoumidis, who launched the SignalGuru project at MIT with Li-Shiuan Peh, an associate professor in the Department of Electrical Engineering and Computer Science who came to MIT from Princeton in fall 2009. But Koukoumidis says even an accuracy of two and half seconds, "could very well help you avoid stopping at an intersection." He also points out that the predictions for variable signals would improve as more cars were outfitted with the system, collecting more data.

Koukoumidis says cars are responsible for 28 percent of the energy consumption and 32 percent of the carbon dioxide emissions in the U.S. and that, "if you can save even a small percentage of that, then you can have a large effect on the energy that the U.S. consumes."

But it isn't just more economical driving that could benefit from the technology. Koukoumidis says the computing infrastructure that underlies the system could be adapted to a variety of applications that could be useful to commuters, such as capturing information about prices at different gas stations, the locations and rates of progress of city buses, or about the availability of parking spaces in urban areas. The system could also be used in conjunction with existing routing software, to recommend ducking down a side street instead of slowing to a crawl to avoid a red light, for instance.

The researchers from MIT and Princeton took out the best-paper award for the SignalGuru system in July at the Association for Computing Machinery's MobiSys conference.

20 years ago in Cologne, Germany there was a similar system. If you followed the digital speed read out in the central reservation, you always got a green light.
Very interesting. I believe this would also reduce traffic accidents..?
Alexander Varwijk
In the Netherlands on some roads there\'s something called a Green Wave. If you stick to the speed limit you should be able to drive through a \'wave\' of green lights.
I don\'t see there\'s any need for technology ... I\'ve been doing this for years. Simply drive at the speed limit. So often I\'ll get passed by cars (sometimes 3 times) and I catch them at the next sit of lights. If I\'m lucky there\'s an empty lane and I just drive right past them while they\'re accelerating away from their pointless stop and they usually can\'t catch up to me again.
It would be necessary to employ city workers with a measurable IQ to work in traffic control.... it hasn\'t happened in the history of mankind.
traffic Lights are timed and configured by chimps with screwdrivers.
Downtown Omaha had a sililarly timed traffic light system in the 80\'s (might still be there for all I know): if you drove 35mph (the speed limit), you nary had to take your foot off the gas nor hit the brake by the time the next signal turned green a block away. Just keep moving through the \"wave\" of green lights.

Loved it, and it encouraged doing the speed limit, and discouraged rabbit-jumping to the next red-light.
Paul Anthony
Okay now if they can just figure out a way to smarten the lights up. How many times do I just sit at an intersection with no cross traffic, then sit and sit some more. Then just as a car comes into view and just before it can make the light, the signal changes and I get to go, leaving that poor sap in the position I was just in.
Q-What\'s worse then missing a light? A-Just barely missing a light.
When I used to live in Portland Oregon they used to have a \"green wave\" down what was then Union Blvd., (later renamed MLK Blvd.) but over the years it was as if they totally forgot about the concept and just let them all go out of sync and then later even put a light rail through it there by destroying any pretext of having a green wave! It was years later that I heard that they were purposely constricting traffic to frustrate people out of there cars and into mass transit, this has never worked and for it\'s size Portland has some of the worst traffic imaginable!
On another note, isn\'t there a program or two in Europe (Germany) that has totally eliminated traffic lights and even speed signs and have cut down dramatically on accidents and congestion?
Gregg Eshelman
Won\'t help a bit with the idiots who deliberately putter along and change their speed to get people behind them caught on red lights.
Why keep humans in the loop at all? Just go to fully autonomous cars and let the computers do the driving. Then humans can concentrate on what they do best in traffic: talk on the phone, text message, eat, recover from hangovers, apply makeup, change clothes, play with the sound system, read, watch TV and movies, play video games, etc. A few people want the feeling of control that goes with driving. Everybody else wouldn\'t mind a digital chauffeur.