Driver training classes teach the rules of their state. Which may not have your beloved "stay right except to pass" rule. Why do you assume that all states have traffic laws identical to Colorado? http://www.mit.edu/~jfc/right.html There are, in fact tourists, who haven't studied the minutiae of driving for every state they visit. Nor does the Colorado DMV give that instruction to new residents. Very difficult to locate "this is how our traffic laws differ from where you come from" information. I know because I tried.