Hi. n00b here, and first post. I'm not strictly a commuter, because I work at home, but I'm rapidly cutting down my car use and expanding my range for local trips. As my wife and I are learning to find our way places by bike, I've been thinking about sidewalks a lot.
I understand the reasons for not using the sidewalk, but on the other hand, I live in a suburb designed only for cars. For several of my frequent destinations, there simply is no practical street route without using sidewalks. One trip includes a significant (for me) climb up a narrow curve with two lanes and no shoulder. The one sidewalk goes the wrong way up the hill, but there are very seldom any peds, and if there are, I'm climbing slowly anyway. After the climb, and a bridge, the road is more hospitable and I can get back in the lane. Another example is a mile of 5-lane 50+ mph highway, also very curvy, but with extra wide empty sidewalks running both ways. Re-routing either of these trips to use better roads would add a minimum of 2 miles, which at my age and fitness level is significant. (The first trip itself is a re-route around a busier freeway entrance cloverleaf with blind curves and no shoulder or sidewalks whatsoever.)
I don't know why I feel the need to justify myself here. Sure, I want to legitimize bikes and take my rightful place as part of traffic, but not enough to endanger myself unnecessarily. I've adopted the idea that any pavement that gets me there in one piece, without endangering anyone else, is good pavement. Is this really the kind of sidewalk riding that some people are bothered by?