I don't know why I am so lucky, but somehow I never ran into this particular sort of trouble with the human race (I do have many other peeves about it though
). People seem to want to help, and it's no different whether you're in a car, on foot or on a bike.
A few years ago my boyfriend was riding his bike downtown Toronto when he noticed his left shoe was completely soaked in blood. He has some bad veins very close to the surface, so even a small scratch can start a huge leak. So he got off his bike, poured the blood out of his shoe
and called me asking to bring bandages. This happened only about a mile away from our house, so I hopped onto a bike and got to the spot within a few minutes of his call. He said in that short time he's had about sixty people enquire about his well-being and offer help. The rivers of blood were pretty spectacular though, that could've been a factor.
In fact, I think if a study were to take place, I'd expect it to find that people are least likely to stop and help somebody in the suburbs. They are just so... impersonal.