In this Tuesday, June 11, 2013 photo, cyclists ride on Milwaukee Avenue in Chicago. The city joins New York, Los Angeles and San Francisco this year in turning loose the nation's larges

 

              In this Tuesday, June 11, 2013 photo, cyclists ride on Milwaukee Avenue in Chicago. The city joins New York, Los Angeles and San Francisco this year in turning loose the nation
In this Tuesday, June 11, 2013 photo, cyclists ride on Milwaukee Avenue in Chicago. The city joins New York, Los Angeles and San Francisco this year in turning loose the nation's largest bike-sharing programs, Divvy, catapulting what was once a way for smaller cities to showcase their eco-friendly qualities into the mainstream transportation options of the country's very largest urban expanses. (AP Photo/Scott Eisen)