Health effects of the London bicycle sharing system: health impact modelling studyBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g425 (Published 13 February 2014) Cite this as: BMJ 2014;348:g425
- James Woodcock, senior research associate1,
- Marko Tainio, career development fellow1, researcher21,
- James Cheshire, lecturer3,
- Oliver O’Brien, research associate3,
- Anna Goodman, lecturer4
- 1UK CRC Centre for Diet and Activity Research, MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Cambridge CB2 0QQ, UK
- 2Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland
- 3Centre for Advanced Spatial Analysis, University College London, London, UK
- 4Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
- Correspondence to: J Woodcock
- Accepted 20 January 2014
Objective To model the impacts of the bicycle sharing system in London on the health of its users.
Design Health impact modelling and evaluation, using a stochastic simulation model.
Setting Central and inner London, England.
Data sources Total population operational registration and usage data for the London cycle hire scheme (collected April 2011-March 2012), surveys of cycle hire users (collected 2011), and London data on travel, physical activity, road traffic collisions, and particulate air pollution (PM2.5, (collected 2005-12).
Participants 578 607 users of the London cycle hire scheme, aged 14 years and over, with an estimated 78% of travel time accounted for by users younger than 45 years.
Main outcome measures Change in lifelong disability adjusted life years (DALYs) based on one year impacts on incidence of disease and injury, modelled through medium term changes in physical activity, road traffic injuries, and exposure to air pollution.
Results Over the year examined the users made 7.4 million cycle hire trips (estimated 71% of cycling time by men). These trips would mostly otherwise have been made on foot (31%) or by public transport (47%). To date there has been a trend towards fewer fatalities and injuries than expected on cycle hire bicycles. Using these observed injury rates, the population benefits from the cycle hire scheme substantially outweighed harms (net change −72 DALYs (95% credible interval −110 to −43) among men using cycle hire per accounting year; −15 (−42 to −6) among women; note that negative DALYs represent a health benefit). When we modelled cycle hire injury rates as being equal to background rates for all cycling in central London, these benefits were smaller and there was no evidence of a benefit among women (change −49 DALYs (−88 to −17) among men; −1 DALY (−27 to 12) among women). This sex difference largely reflected higher road collision fatality rates for female cyclists. At older ages the modelled benefits of cycling were much larger than the harms. Using background injury rates in the youngest age group (15 to 29 years), the medium term benefits and harms were both comparatively small and potentially negative.
Conclusion London’s bicycle sharing system has positive health impacts overall, but these benefits are clearer for men than for women and for older users than for younger users. The potential benefits of cycling may not currently apply to all groups in all settings.
We thank David Ogilvie for comments on an earlier version of this paper, Audrey de Nazelle and Mark Nieuwenhuijsen for advice on air pollution modelling, and Transport for London for the provision of data and comments on draft versions of our methods and results. The views expressed here are those of the authors and do not necessarily reflect those of Transport for London or the study funders.
Contributors: AG and JW had the idea for this study, with AG leading statistical analyses and with JW and MT leading the model implementation. JC and OO’B conducted the modelling of routes and estimation of associated exposure to air pollution. All authors contributed to interpretation of the data and critically revised the manuscript. All authors had full access to all of the data in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. JW is guarantor.
Funding: JW’s contribution to the work was supported by an MRC Population Health Scientist Fellowship and by the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence. This study was supported by the British Heart Foundation, Economic and Social Research Council, Medical Research Council, National Institute for Health Research, and Wellcome Trust, under the auspices of the UK Clinical Research Collaboration. AG contributed to this paper while funded by a postdoctoral fellowship by the National Institute for Health Research (PDF-2010-03-130). The views presented in this paper are those of the authors, and do not necessarily reflect those of any of the study funders.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; JW and AG have received funding from the Greater London Authority for a previous study, none of the authors have other financial relationships with organisations that might have an interest in the submitted work; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by the London School of Hygiene and Tropical Medicine ethics committee (reference 6171).
Data sharing: The integrated transport and health impact model (implemented in Analytica 4.4, Lumina Decision Systems) used in this study, and the statistical analysis do-files (Stata) used to parameterise the model, are available from the corresponding author at.
Transparency: The lead author (JW) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.
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