There are some of those in the Phoenix metro area. Nothing that's really lengthy, but they offer pedestrian bridges in high-traffic areas.
I suppose the only problem with promoting it would be that nobody walks anymore. That's so 1990. Hmm... Maybe if it was tied to a health initiative, so people could feel fit and cool when they used the walkways.
Right. I guess it depends on what part of the country you're in. Walking is preferred in some areas. I guess I got tunnel vision from being in AZ so long.