If you're an involved cyclist in San Francisco, you no doubt already know of this survey.
The San Francisco Senior Action Network is conducting a survey to understand why cyclists ride on the sidewalk in San Francisco. Sidewalk cyclists who have taken the survey so far say they would avoid the sidewalk if more bike lanes were available, if traffic laws were better enforced, and if there were a separate set of traffic laws for cyclists. In a pedestrian survey, 10% of pedestrians answering the survey indicate they have been hit by a cyclist on the sidewalk in the last two years.
This stat is "horse-hockey". The "Cyclists" hitting pedestrians are crackheads on Market between 4th and 9th, oftentimes riding a freshly stolen bike to sell to a slightly less crack-addled fellow who will try to fence it up the line.
I ride on the sidewalk generally for one of two reasons only.
1) Leaving the road for my final destination (home, business, etc...)
2) Bypassing an obstacle - usually a garbage truck with 3 cars lined out behind it and a line of oncoming traffic on the left. I will use the sidewalk occasionally to make a right on red into a road with a bike lane, when a right on red turning car has pinched the curb and is blocked by backed up traffic on the cross street - but only if there are no pedestrians.
As a frequent pedestrian, I am aware of pedestrians when I bike, including those cretins that did not learn "Don't run out into the middle of the block between two parked cars". Everytime I see this happen I briefly tell myself I am going to run over their foot, then I decide that if they insist that they will only learn this lesson the hard way, I will let a car teach that lesson to them.