Originally Posted by
himespau
The other (and much more dangerous to you) threat when it comes to riding on the sidewalk is cars. Yup, you read that right, I said cars. Cars aren't expecting fast moving (even 10-12 mph is fast compared to a pedestrian) bicycles. So they may stop at an intersection and look at what may come in the crosswalk, turn and look the other way, and then pull out. Meanwhile you came from the first direction they looked and have pulled into the crosswalk. They didn't expect you to come that fast and now you're under their tires. Same thing with cars backing out of driveways. The drivers typically only look the short distance a pedestrian would be that could get behind them and don't look the further distance you'd be on your bike that could still result in you getting behind them. Again, you're hit. Being out on the road where you're expected is the safest place to be.
Thank you
himespau, these are the main reasons why it is more dangerous to ride on the sidewalk. Cars aren't looking for a bike on the sidewalk, riding at 12 to 15 MPH is a lot faster than walking at 4 to 6 MPH as a pedestrian. You are much more visible in the street than on the sidewalk.