That would only work in one direction, and it assumes all the streets are clear and there is no discernable traffic. As soon as you add 1 idiot looking at their phone while driving going 15 mph under the limit to make sure they are going slower than the car in front of them it all breaks down.
I just wish they could add proximity sensors in the lights, rather than in a magnetic loop under the light which are expensive to install and maintain. There is no reason for a light to stay red for 2 minutes at midnight on a rural road when there is zero traffic.