To drive from Washington, D. C. to New York, the author is driving through New Jersey, which has 'keep right' laws. And it's general practice across the USA.
"In North American terminology, the passing lane is often known as a left lane or leftmost lane, due to left hand drive (driving on the right).
...
"A common problem arising from misuse of the "fast lane" is that it forces faster moving traffic that wishes to overtake on the left to change lanes, do so on the right, and then change lanes again."
Presumably it is where you live, but it's not universal.