#PHTwitJC 11: Health Impact Assessment Cycling // Car Use -Summary

Next Public Health Twitter Journal Club  will discuss this paper by Rojas-Rueda et al.

Join us on Twitter at 8.00pm UK time (BST) on Sunday 25th March, using the hashtag #PHTwitJC. All are welcome.

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Health Impact Assessment 

According to the World Health Organisation,

Health Impact Assessment (HIA) is a means of assessing the health impacts of policies, plans and projects in diverse economic sectors using quantitative, qualitative and participatory techniques.

The study we are considering this week is based on HIA, although it includes only quantitative techniques for modelling the impact of a shared cycle scheme in Barcelona, Spain.

Public Bike Sharing Schemes

These schemes -PBSS- have been gaining in popularity in cities acCycle scheme Barcelonaross the world, including Paris, Stockholm, Mexico City and London (the so-called ‘Boris bikes’, after the city’s Mayor).  They are intended to encourage active transport use in cities, particularly in the central areas that are subject to traffic congestion. Barcelona’s scheme, Bicing, was introduced in 2007 and is the focus of this paper.


The analysis focuses on all-cause mortality; road traffic accident deaths, and air pollution. It also assesses the effect on carbon emissions. 2009 figures on Bicing take-up were used. The bulk of the analyses reported are based on an assumption that 90% of Bicing journeys would otherwise have been taken by car, although the authors modelled  using differing scenarios.

The study findings are that with a PBSS such as Bicing, reductions in all-cause mortality due to increased physical activity significantly outweigh the increased risks to cyclists compared to motorists, of road traffic accident death  and exposure to air pollution. There is also a modest reduction in carbon emissions due to people switching from car to bike.

The overall conclusion is that:

low cost public bicycle sharing systems aimed at encouraging commuters to cycle are worth implementing in other cities, not only for the health benefits but also for potential co-benefits such as a reduction in air pollution and greenhouse gases.

Questions for Journal Club

  1. Were the aims of the study clear?
  2. Were the parameters used to model health impacts clear, relevant and valid?
  3. Are the findings justifiable considering the information inputted ?
  4. Could anything else explain the results (chance, bias, confounders?)
  5. What implications do the findings have for public health practice & policy?


Full citation:

D. Rojas-Rueda, A. de Nazelle, M. Tainio, M. J. Nieuwenhuijsen (2011) The health risks and benefits of cycling in urban environments compared with car use: health impact assessment study BMJ 343 (aug04 2) p. d4521-d4521 http://www.bmj.com/cgi/content/abstract/343/aug04_2/d4521

Some HIA links:

   HIA Gateway from UK Public Health Observatories. Includes links to various guides (often locally produced)

Healthy Places  -not strictly HIA oriented, but “focuses on legal areas that are new, interesting, often not fully understood, or, not recognised at all as having a potential impact on health in a local area.” Site managed by National Heart Forum (UK)

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One Response to #PHTwitJC 11: Health Impact Assessment Cycling // Car Use -Summary

  1. Pingback: #PHTwitJC 11 – HIA -Reflections on discussion | Public Health Twitter Journal Club

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