it seems as though in this case they're trying to detect 'platoons' or waves of traffic, so if you're traveling along in the vicinity of some cars, they can be detected, and you can still benefit.
Of course; that's how it is now. Car rolls up behind you and you're fine.
The problem is when you're alone and there are no other cars in your lane. If you're totally alone, you can run the red light, if there is other traffic just not in your lane you're screwed.
