I'm not going into detail about how I come to be such an authority on this but I learned something while away. I learned about the Move Over Law, and that 70% of the drivers in the US have never heard of it.
Simply, Move Over is legislated good manners. The many variations of the law state that IF an emergency vehicle is stopped at the side of the road THEN a driver MUST either change lanes to be away from the vehicle or slow to 20 MPH below the posted speed limit. The penalty for failure to comply is steep. Thankfully, I have no personal experience with such matters.
If you are travelling the highways and biways this long weekend, be careful, have fun, move over.