U.S. cities are not known for their bikeability, especially by European standards. However, things have been slowly improving over the last few years, as new infrastructure (and bike-sharing schemes) are added, and the safety-in-numbers effect encourages new cyclists to the road. Last year, the number of protected bike lanes almost doubled, with a similar jump expected in 2013.
Via Fast Company Co.Exist comes this story about "Bike Score", the web site that rates the bikeability of cities. With a rating scale of 1 - 100 rating the city for for overall bikability to color coded maps showing more detailed views of the cities by using heat maps to visually depict the best and worst areas for commuting.
The site uses data from 4 categories to come up with the rating: