Firstly, googling "cycling 20 mph", the first result is "20mph is a speed most cyclists are not able to average."
Setting that aside, this is the exact purpose of speed limits, not one-way streets. One-way streets do not prevent pedestrians from popping out behind "bends, turns, hills/humps, or other obstructions", or children, or debris, or potholes, or stopped or malfunctioning cars, or construction, or sudden road ends...
Edit: If you can't stop in time for a bicycle, you can't stop in time for anything, and you need to drive slower. Unfortunately, many American drivers seem to believe that they own the road, and if dumb children run out onto the road and get flattened, that's their own fault for breaking the law.
Setting that aside, this is the exact purpose of speed limits, not one-way streets. One-way streets do not prevent pedestrians from popping out behind "bends, turns, hills/humps, or other obstructions", or children, or debris, or potholes, or stopped or malfunctioning cars, or construction, or sudden road ends...
Edit: If you can't stop in time for a bicycle, you can't stop in time for anything, and you need to drive slower. Unfortunately, many American drivers seem to believe that they own the road, and if dumb children run out onto the road and get flattened, that's their own fault for breaking the law.