SignalGuru uses a smartphone camera to help you manage traffic lights, save fuel

Nothing burns fuel (or patience) faster than stop and go traffic, something MIT researchers are hoping to minimize with SignalGuru. The smartphone-based system commands you to slow down or speed up based on whether the light is green, yellow or red to help avoid gas-guzzling activities like idling and accelerating - reducing fuel consumption by 20 percent. Unlike Audi's Travolution system that relies on WiFi and 3G to communicate with traffic lights, this latest development uses your smartphone's camera to detect signal status and create a Green Light Optimal Speed Advisory (GLOSA), which will predict and learn traffic light patterns.

Engadget, SignalGuru uses a smartphone camera to help you manage traffic lights, save fuel