IBM has filed a patent application for a smart traffic signal communication system, where a traffic signal would communicate with the queued cars, telling them to shut down their engines, and scheduling when to restart their engines, based on where in the queue each car is. From Slashdot.
This is not a bad idea, but it may be overly complicated and expensive. Automakers and suppliers, including my own employer, are actively working on engine start-stop systems which will prevent long engine idling by shutting down the engine if the vehicle comes to a standstill for more than a few seconds. The engine is then restarted when the driver lifts off of the brake pedal. It sounds like the IBM proposed system would save a few seconds of idle time per car, and perhaps schedule a smoother restart, but at the cost of additional electronics at each intersection, and in each vehicle.
There is also a question about consumer acceptance of the traffic signal system being able to shut down your car.
