When people stop at lights, they usually pull up much closer to the car in front of them than when they're moving. It is rather wise to wait until the car in front of you has pulled away to a safer distance before you go. If everyone stopped farther back so they could start moving at the same time, I doubt they would get through the intersection any sooner. They would just start out farther from the intersection.

You also shouldn't start to go as soon as the light changes because you can't count on the guy in front of you pulling away as fast as you, even if he's been signalled in advance. If you hit the gas but he doesn't, you will have to brake again. That would tend to cause a "slinky" effect in the cars behind you that would make traffic even less fluid.

I don't know about anyone else but when I'm at the front of the line I tend to watch the lights for the cross traffic. About 5 seconds after their lights turn red mine turns green and I'm going.

I do suppose that most people are not as impatient as me tho'. And for that reason staging yellow prior to green isn't going to speed things up.

I've often thought this, and agree it is 'wasted' time. Unfortunately it's part of living with the human race. All it takes is one person to get it wrong and everyone behind is effected.

Not sure how this affects your idea, but it is always a good idea to keep some space between yourself and other drivers. Because everyone stacks up at a light, we need to regain the safety margin. I suppose we could work out a way to have everyone advance more quickly at the light, then correct their distance later, but this would require some Blue Angels-level coordination.