This research report, published in the British Medical Journal in June 2011, estimates the risks and benefits to health of travel by bicycle, using a bicycle sharing scheme, compared with travel by car in an urban environment. The study used the public bicycle sharing initiative, Bicing, in Barcelona, Spain as its setting. The study found that by using the bike share scheme, the annual number of deaths avoided was 12.28 and annual carbon dioxide emissions were reduced by an estimated 9 062 344 kg.

The Bicing initiative has been highly successful in terms of number of subscribers and led to a large increase in trips on bicycles, which is often hard to achieve. A previous study showed that interventions generally led to an average 3% increase in the prevalence of cycling in the population. Bicing so far has increased the number of cycling trips by 30%. Eleven per cent of the population in Barcelona subscribes to Bicing, although it is estimated that only 1.7% of the population are regular users.
Abstract
Objective
To estimate the risks and benefits to health of travel by bicycle,using a bicycle sharing scheme, compared with travel by car in an urban environment.
Design
Health impact assessment study.Setting Public bicycle sharing initiative, Bicing, in Barcelona, Spain.Participants 181 982 Bicing subscribers.
Main outcomes measures
The primary outcome measure was all cause mortality for the three domains of physical activity, air pollution (exposure to particulate matter <2.5 μm), and road traffic incidents. The secondary outcome was change in levels of carbon dioxide emissions.
Results
Compared with car users the estimated annual change inmortality of the Barcelona residents using Bicing (n=181 982) was 0.03 deaths from road traffic incidents and 0.13 deaths from air pollution. As a result of physical activity, 12.46 deaths were avoided (benefit:risk ratio77). The annual number of deaths avoided was 12.28. As a result ofjourneys by Bicing, annual carbon dioxide emissions were reduced byan estimated 9 062 344 kg.
Conclusions
Public bicycle sharing initiatives such as Bicing in Barcelona have greater benefits than risks to health and reduce carbon dioxide emissions.
The health risks and benefits of cycling in urban environments compared with car use: health impact assessment study | PDF of full article
David Rojas-Rueda, Audrey de Nazelle researcher, Marko Tainioresearcher, Mark J Nieuwenhuijsen
BMJ 2011;343:d4521 doi: 10.1136/bmj.d4521