I make no attempt to physically enforce "slower traffic keep right." But I often see friends driving the speed limit in the far left lane, and they won't switch

I make no attempt to physically enforce "slower traffic keep right." But I often see friends driving the speed limit in the far left lane, and they won't switch lanes when somebody comes up behind them because they are "trying to slow down the speeders." That's the part that needs a badge. Anybody can express an opinion. It's when you physically try to force people to behave differently that you need a badge. By "normal flow" I'm referring to highway conventions that expect the average traffic speed of a leftward lane to be higher than the lane immediately to its right. That's a safer flow than having every lane with a random average speed. Germany enforces this on the Autobahn. Some US states enforce it; most have signs promoting the idea. With "slower traffic keep right" you get something close to laminar flow (with shear) if you treat cars as gas molecules. With "every lane can do whatever it wants" you have turbulent flow, more lane changes, and more collisions.