Over the last few years, the bike-sharing system has exploded in cities throughout the world. The system enables citizens to pick up bicycles at some point in the city, then drop them off at another point in the city for a small fee. A great alternative to hailing or cab or getting stuck in city traffic, the bike-sharing system has proven effective at combating urban traffic and has recently spread to 855 cities worldwide.

They started this in Madrid, Spain when I was living there and I loved it! However, many cities are not built for biking. Madrid for example had few biking lanes, and many parts of the city were very dangerous for bikers. Would be interested to see accident rates for the bike-sharing systems.