But you could jump off at any speed - or get jostled and fall off accidentally if hanging on to the pole that was provided in the doorway. Falling into traffic

But you could jump off at any speed - or get jostled and fall off accidentally if hanging on to the pole that was provided in the doorway. Falling into traffic at 30mph isn’t a bundle of laughs either My guess is the door requirement was to avoid needing to scrape people off the single lane roadway in rush hour more than a thought for passenger safety and that difference may have got lost on the way to the page