To be clear, those are usually for any handicap, as they are outfitted with wheelchair access and usually have extra adults riding along to help.
They are (or at least were in my area at that time) much more comfortable, similar to public transit busses. I got to ride along with a friend with a muscular problem on one a few times in the late 90s early noughties and it was lux.
The floor definitely gives you a new perspective.