That is indeed the rule in European countries I've driven in and (modified for which side of the road is being driven on) some US states (like Oregon) have simi

That is indeed the rule in European countries I've driven in and (modified for which side of the road is being driven on) some US states (like Oregon) have similar rules. California, on the other hand, allows people to drive in whatever lane they feel like for however long they feel like as long as they maintain sufficient speed. The slower traffic is supposed to stay to the right and the faster traffic is supposed to stay to the left. The police can intervene if they feel that someone is driving too slow in the wrong lane, but I've never seen that happen. There are no rules in California to prevent overtaking on the right, so you can choose which lane you want to move into to overtake someone.