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.
Bike sharing has risen in popularity around the world, in cities like Paris, Washington, D.C., and New York City. Most recently, we reported that bike sharing is coming to San Francisco. Those bikes will come with GPS systems to make them harder to steal.