Originally Posted by
PatrickGSR94
At what age does it become stupid, dangerous, or illegal to ride a bike on the sidewalk?
Stupid - when you're inconsiderate to other users of the sidewalk.
Dangerous - when you put other users of the sidewalk in danger by your conduct.
It can be entirely safe and sensible to ride on the sidewalk at any age, as long as one is considerate of pedestrians and other users.
When it becomes illegal depends on the area.