And I've come close to being hit by one traveling at a high rate of speed. It happened a few years ago as I was leaving work. I had just stepped outside the workplace door, (which is recessed from the sidewalk by about ten feet), walked the ten feet to the edge of the sidewalk, and as I cleared the recess and was about to step onto the sidewalk, a bicyclist came barreling down the sidewalk and missed me by less than a foot. If he would have hit me, it would have meant the hospital for sure or worse.
That probably got the old adrenalin going!