There are two laws that I noticed as we did a ten week trip around the USA that I think should be part of Interstate regs. In one state the have a fairly long stretch between the far right lane and the adjacent lane where changing lanes to the right is prohibited. I also saw a lot of people change to the right because the off ramp preceding the on ramp has space due to drivers exiting. I think it opens up a lot of real estate for merging vehicles from the on ramps.
The second is a law that says when you get to a merge right or left, you are suppose to do that as soon as it is safe, not speed up and force your way in at the last minute.
Those are just two of many laws that are really just common sense IMHO.