Bike-shares proliferate worldwide: the numbers behind 12 cities’ green initiatives

Bicycles are the world’s most popular form of transit: About 133 million were produced last year, a nearly 600% increase from 1960 and more than twice the number of cars manufactured in 2011. Sharing programs, where members can pick up and drop off bikes at street-side rental stations, are on the rise in cities. In 2007 there were 60 such programs worldwide; today there are nearly 450. And soon, New York City.