Sidewalks are for pedestrians, which means when you ride there you should ride as walking speed. Certainly no faster than jogging speed. Kids are allowed to ride on sidewalks because they're safer there and they aren't going that fast. There is ONE place that I ride on the sidewalk - I live on a busy street, near an intersection with another busy street, so when I'm approaching my house on the opposite side of the street, I'll swing over to the other side for the last 20-40 yards, and if the sidewalk is empty, I'll take it, at fast walking speed, to get to my house.
Drivers look for hazards in the customary places, moving in the customary direction, at the customary speed. On sidewalks, we expect people moving in either direction at walking speed. On the road, whether in the traffic lane or bike lane, we expect other vehicles moving only in one direction, at a greater speed. If you ride on the sidewalk at greater than walking speed, you're moving at an unexpected speed in an unexpected place, possibly in an unexpected direction.
And stop calling us "cagers".
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"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles