Buses between schools and for country kids always had all ages.
As far as I know, all city buses would have all ages, too.
Really? What state was that in? We had at least two, if not three, tiers by ages.
City bus yes but this was a school bus. Our school buses never had Grade school kids with Junior and Senior high kids together.
The Grade school kids got out before Junior and senior high. So they got picked up and dropped off first then those same busses picked up both the Junior and Senior high kids.