"This amazing Polymaps project from SimpleGeo and Stamen shows where San Francisco's roads are a little worse for the wear. The "Pavement Condition Index Map" illustrates the condition of the street pavement across the city, pointing out in a very visual way where the asphalt needs a little TLC. Why do we care? Because cities that have smooth, safe roads are better for bicyclists -- oh, and hypermilers too. Check out how the team pulled together the information."
Treehugger shows the map and how it works. High quality roads are shown in green, and roads in poor shape are displayed in red.