There are a couple of tricky spots in which I resort to sidewalk cycling, but it is generally safer to ride in the street. Driveway cuts and intersections are particularly deadily for sidewalk cyclists. When a cyclist wants or needs to travel against traffic, such as to avoid a dangerous left turn (or, in my case, two consecutive left turns on multilane arterial highways), he/she definitely belongs on the sidewalk, to avoid endangering lawful vehicular cyclists. Of course, when on the sidewalk, one must respect pedestrians' real and perceived safety.