A study of Barcelona's bike-sharing program -- called Bicing -- showed that the system not only saved 9,000 tons of pollution from carbon dioxide, but it also led to 12 fewer cycling deaths a year. The study was published last week in the British Medical Journal.
Even though there were small estimated increases in cyclists' deaths from traffic accidents and air pollution -- 0.03 extra deaths and 0.13 deaths each year, respectively -- the study found that about 12 lives were saved from the extra heart-healthy exercise per year.
The overall health benefits of physical activity from cycling outweighed the risks of bike sharing: inhaling air pollutants and road traffic incidents, researchers wrote.
About 180,000 people participated in the Bicing bike-share program by August 2009, and the average person biked an average of roughly two miles a day, researchers reported.