Get more cars through each change of light
Make traffic lights give a signal they are about to turn green so that the first car won't be sitting there not going when it is clear.
In safety conscious Scandinavian/Northern European countries traffic lights have long been set to signal the upcoming light change to green by lighting up the yellow light while the red light is still lit, just before it turns green. This gives the first vehicle in line a better chance to get going in a timely way and should allow more vehicles behind to make it through the intersection in one light change. I believe the law is pretty clear that one cannot proceed through an intersection until your light is green and even then one must check the intersection to see that it is clear before proceeding through it so there should be no change in liability for collisions and the red light runners shouldn't be able to spoil things more than they already do. The result of this change to the light sequence, which is intuitive, would be less time-wasting and polluting waiting at intersections. It would seem to be a simple programming change as opposed to an equipment change and thus shouldn't be expensive and yet might have a significant effect on many commutes.
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