Isn't this issue always answered with common sense? I prefer the bike lane when it's available, but if it isn't I'm not bashful about using the sidewalk. I'll ride in the right lane in light traffic, but heavy traffic represents too much risk: drivers putting on makeup, adjusting hair, talking/texting on cell phones, drunks, old folks and teen agers just raise the fear factor beyond my limit. I'd rather get a sidewalk citation than get side-swiped by a teen ager texting his girl friend. Construction zones are an automatic pass to use the walk.
In communities where substantial effort and cost have given us dedicated bike lanes, I feel obligated to use them as much as practicable. During rush hour traffic, I often stay home or will use the walkway to avoid competing for space. I just observed the driver of a huge dump truck blast through an intersection on pink with the cell phone pressed to his ear. The width of his vehicle gives little quarter to anything it passes; it's a deadly threat when the driver's attention isn't devoted 100% to safe operation.