In a paper published today in the British Medical Journal, researchers at the Center for Research in Environmental Epidemiology in Barcelona report that the city's public bike programme - Bicing - saves lives and reduces greenhouse gas emissions.
The research has relevance for the 360 public bike schemes operating globally, including London's 'Boris Bike' scheme, a scheme originated by the previous Mayor of London, Ken Livingstone.
The Barcelona study found that around 9,000 tonnes of carbon dioxide pollution are averted and 12 lives saved each year by Bicing, which was introduced in March 2007.
Lead researcher David Rojas-Rueda said:
"Active transport policies such as bike sharing systems promote physical activity among the population and are a good means to improve public health and also reduce expenses in public health services."
The research estimated the number of deaths associated with travelling by bike compared with driving for three main factors -- physical activity, road traffic incidents, and exposure to air pollution.
They calculated an annual increase of 0.13 deaths from air pollution and 0.03 deaths from traffic incidents among cyclists compared with car users.
But as a result of increased exercise and extrapolated better health, 12.46 deaths were avoided, making a total of 12.28 deaths avoided among cyclists every year.
Rojas-Rueda said it was important "to encourage cities to change car use by cycling and stimulate the implementation of bike sharing systems in cities to improve the health of the population."