Moving over to allow faster-moving traffic to get by is a wonderful concept. But I’d take it a step farther: If you’re not passing, you should not be in the left lane at all.
That, at any rate, is the way it’s done in Germany. There is a reason why. It is called closing speed. If a Porsche turbo doing 140 is bearing down on a Fiat 500 doing 70, the Fiat driver had better notice the headlights getting much larger, much faster in his rearview – and get the hell out of the way in time.
Which he usually does. Which is why the German Autobahn is a safer place – without speed limits – than U.S. highways are with speed limits.
German drivers are taught to use the passing lane only to pass. They don’t set the cruise control and zone out or gabble on their cell phones like so many American drivers unfortunately do. Instead, they use scan their rearview and side mirrors so that they are always aware of the ebb and flow of traffic around them. They anticipate the need to yield to a faster-moving vehicle such that the faster moving vehicle’s driver does not have to abruptly slow then maneuver to get around a dawdler. Traffic thus flows. And, high-speed traffic can mingle with lower-speed traffic safely.