I've ridden all my life in an urban area, and I know what I do, and I know what I've seen many other people do, and one of the most suprising things to me being new to this forum is the number of people with strong opinions about riding on the sidewalk. I typically ride in the road because I find it more convenient (it gets old bumping up and down curbs, and I feel I can responsibly go faster), but there are rare instances when I want to be on the sidewalk. If I'm near pedestrians I slow down to pedestrian speeds, but I do this on MUPs as well. In fact I avoid MUPs in my area on nice weekends because they're populated enough I don't feel responsible riding fast on them. I've seen many elderely folks get frightened and nearly hit, and children nearly getting hit by pacelines. It's very, very rare, but if I approach a crowd on sidewalk or at event then I do get off and walk. I've seen "the driver" the OP appears to describe and he would just as easly hit a pedestrian particularly a small child because he's not looking period. I had nearly the same incident as OP however I WAS in the road with right of way and nearly T-boned driver blowing stop sign, he never even saw it. I locked them up and couldn't reproduce the manuever to avoid clipping him and not crashing in another 1000 tries. Contrary to other posters I've never had incident with pedestrian or vehicle due to detour onto sidewalk. The majority of incidents I've had are road rage over me being in the road. I think as long as it's legal and you ride to the conditions it's ok to ride anywhere you want.