It's about time somebody did a study like this. I don't know how many times I've sat at a red light with no cross traffic thinking about how much gas is wasted in such situations.
Near my home (southeastern Pennsylvania), if you pull up to an intersection and there's no traffic in the opposing direction, the light changes so you get a near-immediate green. It works great at night when nobody else is near the intersections.
I noticed the same thing when I lived in Seattle for a few months.
I doubt the signals are communicating with each other, but there is definitely some deployment of signals with sensors to detect whether a car is waiting on each side of the intersection.
I noticed the same thing when I lived in Seattle for a few months.
I doubt the signals are communicating with each other, but there is definitely some deployment of signals with sensors to detect whether a car is waiting on each side of the intersection.