I'm still new enough to the world of commuting that my opinions are evolving... initially it seemed ridiculous avoid riding on sidewalks. My own safety being my primary concern (and not contradictory to the safety of pedestrians on the sidewalks since it does me no good to hit them), I want to retain the greatest amount of control over my safety. On the sidewalks I have control, and on the street, the masses of random drivers have control. I have a friend who brags about how many bikers he has hit with his massive truck and I know he's not a solitary case (our fraternal bond goes back a ways and forces me to tolerate to an extent the fact that often he is a dumb, obnoxious m*f*er). Yes, a bicycle is considered a vehicle by law... but lets be honest... a bike is not a car, and I can't see much benefit in deluding yourself into thinking it is. In my city it is technically prohibited to ride on sidewalks, but it is clearly an unenforced law as I see people riding on sidewalks constantly (I have a view of a street that has a dedicated bike lane at work and even see people riding on the sidewalks there.)t

Now, however, I do ride on the street 95% of the time. I've gotten comfortable enough with various streets to know which ones are bike friendly (either dedicated lanes or simply have enough room for cars to pass bicycles without moving into another lane). And it is far more convenient to ride on streets. Still, for small stretches I have to ride on streets that do not have room for both bikes and cars, and when it's busy, heck yeah I'll ride on the sidewalk. If I do encounter pedestrians I yield, and I don't find the situation altogether dissimilar to encountering pedestrians on bike trails, except on the trails I'm going much faster.

My opinion has changed, yet I still can't climb aboard the dogmatic POV that it's always dangerous and stupid to ride on sidewalks. To me it's dangerous and stupid to assume no other drivers exist like my stupid friend.