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 in mortality 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 ratio 77). The annual number of deaths avoided was 12.28. As a result of journeys by Bicing, annual carbon dioxide emissions were reduced by an 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.