Please make it legal on the arterials and in densely populated areas.

Paint a green line on the sidewalk for the bikers to follow and the pedestrians to avoid.

In my area all bikers use the sidewalks now because of heavy traffic and U-turns at 19 Ave/Camelback, which is where the Metro turns.

I've read many comments about shared pathways - along the canals, for instance - that I believe that we could treat some sidewalks as pathways, legally. And considering that we've been doing it for years here and in other densely populated areas, it seems to be safe enough.