Once I was riding down a short but steep hill, one block long. On the sidewalk was a girl on a bicycle doing about the same speed as I was but maybe 30 feet ahead of me. At the bottom of the hill there was an alley. Suddenly a car came out of the alley, and stopped to let the traffic (me) go by. The girl riding on the sidewalk slammed into the side of the car and the girl went over the hood. We all had to wait for the police to come.