Yes, we have some bus services (Greyhound, like in the movies, and a bus that goes between towns once a day) but I've never been on one and don't know anyone who has. Kids begin driving age 16 and under that age are typically driven places by a friend or parent, so there's not much need for busses.

Also: younger kids are ferried back and forth to school in special yellow busses that are only used for school service. So actually there _is_ a widespread public transport service all over the US but people don't think of it as such because it's run by the schools and only usable by school kids. Some companies run their own busses too for their workers, to and from the plant, to suit shift hours.