On my commute in to work this morning my typical expressway speed was in the 65 - 75 range on nominally 55 roads. I passed some people and in turn was passed by others. There was a cop on one stretch who slowed everyone down to the speed he was going (70), but when he turned off things got back to normal. Those who were going 55 (only a few) were causing the traffic to bunch up and people to pass even though they weren't in the left lane.
If someone wants to go faster than I am go for it. I'll get out of your way. OTO if you're going slower than I am get out of my way.