I *loved* driving in Germany and Austria when I was there for almost 3 weeks in 2013.
I think the best thing done in Europe that isn't done any more in the US is observation of "lane courtesy." Too many Americans park themselves in the left most lane thinking, incorrectly, that it is the "fast lane" when in fact all lanes are *passing lanes.* If you aren't passing anyone, get the heck over as far right as possible and traffic speeds along ever so smoothly.
But macho and dumb Americans think they must be driving fast if they're in the left so they are better than the other drivers. Not so. Just move over and make it easier for everyone to flow in traffic.
As an aside, it is legal to pass *on the right* in almost every state if there is a proper lane for it (no passing in the shoulder). Check out your state's laws and if it is legal, DO IT. You'll save yourself so much time and frustration.
Another thing Europe does is actually have federal laws regarding driving. In the US, each state does it differently, so driver education is a mishmash. What you learn in one state does not necessarily apply in another, though most of it does.
Lastly (and I really wish the US would adopt this on Interstates), many highways have designations that trucks must use the rightmost lane *only*, usually in more urban or suburban areas. This is such a great idea! Trucks typically move slower than other vehicles so they can stay in the right lanes. This means that people who merge onto the highway can do so at slower speeds than the maximum allowed. They just have to be aware of large vehicles nearby and take some responsibility. Once up to speed, cars can pass all the trucks on the left with 2-3 lanes to work with. If trucks park themselves in the second lane of a 3-lane highway, there is no room to maneuver around them, and it slows everyone down.
/off soapbox