Smart phones can provide music, movie times, bus schedules. They can even make phone calls! And now, they might help cut down fuel use while driving. That is, if enough are used in a system called SignalGuru developed by researchers at M.I.T. and Princeton.

A network of smartphones mounted on vehicle dashboards captures and transmits images of traffic signals. The SignalGuru software then analyzes the data to predict traffic signal patterns. If the light ahead is red, the driver is told the optimal speed to avoid stopping and idling. Or told to make a slight route change that avoids a stop. Because idling and accelerating significantly increase fuel consumption.

The system was tested in Cambridge, Massachusetts, where traffic lights are on a set pattern. And in Singapore, where signals respond to traffic flow. And drivers slashed their fuel use by about 20 percent on average. The study won a best-paper award at the Association for Computing Machinery’s MobiSys Conference. [Emmanouil Koukoumidis, Li-Shiuan Peh and Margaret Martonosi, "SignalGuru: Leveraging Mobile Phones for Collaborative Traffic Signal Schedule Advisory"]

The researchers say the platform could work for a variety of driving tips—prices at gas stations, or parking availability. And a bonus: with the phone mounted on the dashboard, you can’t text and drive.

—Cynthia Graber

[The above text is a transcript of this podcast.]