I think something like that exists, but at multiple successive crossings there could be a problem in getting total traffic moving without some sort of general coordination.

There have been traffic sensing loops in the pavement for years now. Other not so recent innovations can do exactly what you want.

A look inside the control boxes reveals computers that can not only count cars but make adjustments for time of day, power outages, and other variables.

Additionally, all this can be overridden by emergency vehicles, allowing them to stop traffic in all directions as they approach.

And, as most of us have noticed, they can recognize "your" car and ensure that you get to stop at all the intersections for red lights . . . ;-)

I think that peconic has stumbled on an idea that only recently has been being put into traffic control systems.

Like Hyenuf said, presence loops have been in intersections for decades, but generally, they only sensed that there was "a" car in a particular lane, never caring past the first. The software wasn't smart enough (or no software at all) to even care if there was more than one car waiting--it just went through it's routine, with no timing changes.

But now we have presence detecting cameras above many intersections. They're a big change to this industry. Loops are expensive and have a high failure rate, so trying to add two or three to one lane was never worthwhile. And trying to write code to read them successively and prioritize is heck. But with the new context-recognition cameras, I understand that the computer can literally count the cars and the software now is smart enough to adjust timing to make use of it. Look for a tall camera on a pole above newer intersections--usually by the left turn signal, etc. People aren't looking at that camera's output--the computer is.