Depends on the city though. Bus routes in London haven't changed for a long time. The buses I used 30 years ago all have basically the same routes. There are pr

Depends on the city though. Bus routes in London haven't changed for a long time. The buses I used 30 years ago all have basically the same routes. There are probably routes that are over 80 years old. But buses could never be grade separated in London. There's just not enough room.