Have you ever thought about the term 'pedestrian'?
That's an actual human in her/his normal i.e. natural mode of transport.
Why don't we call pedestrians humans then?
@cweickhmann How do you distinguish them from humans in cars and humans on bikes and humans on.. on.. on..?
Pedestrian = human on foot.
@trinsec That's my point: Would you say "horse on hooves"? No. That's a horse.