It is natural to look for safer places to ride your bicycle considering the risk of serious injury that comes with riding in the street. However, a sidewalk may not necessarily be better for you. In fact, it could be a more dangerous location to ride.
WebMD describes some hazards you might encounter if you take a bike outing onto a sidewalk.
A crowded sidewalk is easy to avoid. However, an empty sidewalk could fill up with pedestrians as your ride progresses. Even a single person could be a collision risk. Many people out walking might not anticipate sharing a sidewalk with bike riders, so they may not be on watch for you.
Other bike riders could have the same idea as you to ride on the sidewalk. However, they may have less experience than you and do not know how to maneuver well enough to avoid other bicycles at close range. You could also encounter children on their bikes who are just beginning to learn riding.
Sidewalks have their share of standing objects close by, so it is possible to crash into one if you do not notice it. Common examples include parking meters, lampposts and hydrants. Garbage piles on the curb are another consideration, especially if you ride in a neighborhood.
While riding on a road puts you closer to automobile traffic, you are at least riding in an environment where many drivers expect you to be. Sidewalks offer their share of obstacles as well as unwary pedestrians, so bike riders should consider other places to enjoy a ride.