SignalGuru Helps Drivers Avoid Red Lights
cylonlover writes "Researchers at MIT and Princeton have now devised a system, dubbed SignalGuru (PDF), 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." In their testing, the system saved drivers about 20 percent in fuel.
(with the shift stick in neutral, so the car doesn't brake on the engine)
On a modern car this is bad for fuel consumption - in neutral, the engine is burning fuel to idle, but under engine-braking conditions the ECU cuts the fuel entirely. So if you used the brakes (wasting kinetic energy as heat) and then put the car in neutral to avoid slowing down further, you wasted a load of fuel. Better to just let the engine brake the whole way.
http://blog.nexusuk.org