Mostly yes, but it actually varies a little more than that on a state-by-state basis:

https://jalopnik.com/5501615/left-la...e-by-state-map

Six states basically have no legal requirement to keep right. 10 states have German-style "keep right except to pass" laws, while the remaining 34 states have some form of the left lane being reserved for "faster" traffic.

Edit: the above was from a 2010 article; here's a more up-to-date article albeit one that isn't written as clearly: https://www.autoinsurance.org/keep-r...-passing-only/

My experience living in Pennsylvania for 6 years and having driven extensively in all 50 states is that Pennsylvania is the best when it comes to keeping right except to pass. Not coincidentally, it's one of the minority of states that has a defined stay-right law. Perhaps more interesting is the fact that Washington, which has some of the worst examples of drivers aimlessly staying left even when driving slower than traffic and slower than the speed limit, has a stay-right law. There's been pretty extensive coverage in the media of increasing enforcement of that law to try to change the public's behavior. (Here's an article from last year: https://www.seattletimes.com/seattle...-lane-camping/, and a WSP-produced video on the topic can be found here: .)

IME, the worst examples of this behavior are focused on the west coast (I've long suspected that not coincidentally, that's the region of the country where people tend to refer to it as "the fast lane" rather than "the passing lane," because they think they can hang out in it as long as they're going "fast enough"), with the behavior (on average) decreasing as you move further and further east towards Pennsylvania. (It gets slightly worse if you keep going further north/east past Pennsylvania, though in NY and New England, people in all lanes tend to wildly ignore the speed limit, so at least you don't end up with the Washington/Oregon-style line of frustrated drivers behind some loser poking along in the left lane blocking traffic...)