I pretty much ignored this thread until I saw the post about PM's, so I took a gander over here.

In Montgomery County, Maryland, it is legal to ride on sidewalks in the business district. In fact, their multi-modal transportation hub (both current and planned revisions) in the downtown Silver Spring area (where I work) integrates hiker/biker trails right alongside the bus depot with bike parking right at the mouth of the entrance to the Metro (subway) station. It's all one big mish-mash. There is no viable way for me to get to my office via bicycle without spending at least SOME time on the sidewalk.