A group of researchers at MIT and Princeton University are testing to figure out how to best save fuel when stopping and re-starting cars at traffic lights, and they're using the iPhone to do so. The smartphone is mounted on the car's dashboard, and uses the camera and GPS information in a system called SignalGuru that tells the driver when it's best to slow the car down in order to save fuel (so you're not always revving up the engine and then having to put on the brakes when the next light pops up). The system works, apparently, and in Cambridge, MA testing, fuel consumption was cut down by 20 percent.
The system was also tested in Singapore, where most traffic lights change the length they're displayed based on the traffic around them. In t
