The Oil Drum: Local

WNC - I agree about both the increase in public spaces/buildings and safe hitchhiking communities.

Public spaces/buildings: The worst place to get caught out in the rain is a single-use zone solely for the purposes of a private property owner. Some of this is something that can be done by simply creating more mixed land uses. My favorite place to pop-in during a storm is a local coffee shop, bar or pizza parlor. Libraries and public spaces inside large building lobbies also work and don't cost anything. The other way would be to create shared places on the edges of public/private property - like little sheds on the side of the road with water, air for bike tires, whatever the private property owner or local municipality could easily provide cheaply.

Hitch-hiking community: Some of this could just be accomplished through greater familiarity with your neighbors and it could also be done in other ways through technology. Many ride-share web sites allow members to build their credibility and reliability by getting ratings from prior experiences similar to e-bay. I could imagine a service that allows people to request a pick-up through their cell phone and have a trustworthiness rating sent to a potential ride going in their direction.