LancsLad said:
I drive in the US quitw a bit but I am not really sure if it is a law or just by convention that they do that. It does speed things up, but in England it is strictly enforced. I almost think that there is some unwritten gentlemens type agreement that if someone is slow in the third lane and you come up behind them. If they don't move over you can follow them to the next lay-by and throttle them. That last bit is just a perception but drivers take it very seriously. Do not get in the way of anybody in the third lane no matter how fast you are going.
In most U.S. states, its convention to share the road. Some do it fear of vehicle behind may possess firearm, with cases of road rage years ago.
Some states do enforce it if they see vehicle typing up traffic.
Lancs, U.K. has the pre-green flashing light to warn drivers of upcoming green, I can't recall the sequence. I like at night, many intersection turns to flashing amber instead of red for cars to pass intersection with caution, reduce wasting fuel idle at traffic lights & those roundabouts.
Much more civilized.