MRC Epidemiology UnitAims of the study
The primary aim was to assess the magnitude, nature and population distribution of changes in the travel behaviour of commuters who travel to work in Cambridge associated with the opening of the Cambridgeshire Guided Busway.
The secondary aim was to identify, explore and explain the wider health impacts of any observed changes in travel behaviour, specifically in terms of changes in overall physical activity, wellbeing, sickness absence, and carbon emissions
Design
Quasi-experimental study
Overall research design
The study design was adapted over time to accommodate repeated delays in the completion of the intervention that were outside the control of the research team. The original design envisaged collecting the main outcome measures in 2010 and repeating these in 2011 following scheduled completion of the busway in 2009, but in the event the busway was not opened until August 2011. This allowed for an extended period of methodological and observational research to enhance the ultimate evaluation, which was based on quasi-experimental analysis of a cohort of commuters followed from 2009 to 2012 together with a survey of busway users and a set of qualitative studies. A graded measure of each participant’s exposure to the intervention, based on the proximity of the busway to his or her home, served as the basis for controlled comparisons.
Participant recruitment and data collection
The study comprised four main elements:
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A cohort study of adults living within approximately 30 km of Cambridge city centre and working in areas of the city to be served by the busway. Participants were recruited predominantly through workplaces and surveyed by post. They completed a core questionnaire in 2009 and were invited to complete annual follow-up questionnaires until 2012. A total of 1143 participants provided valid data on active commuting at baseline, of whom 470 also did so at final follow-up in 2012.
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A face-to-face survey of 1710 users intercepted on the busway in 2012.
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Detailed quantitative studies of the activity patterns of subsamples of the cohort, using household travel diaries (865 person-weeks of observation) and various combinations of accelerometers, combined heart rate and movement sensors and global positioning system receivers (2609 person-weeks of observation).
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Detailed qualitative studies of subsamples of cohort and intercept survey participants, using over 120 semistructured interviews complemented by a photo-elicitation study, a media analysis and a participant observation study.
Investigators
Principal investigator
Dr David Ogilvie – University of Cambridge
Co-investigators
Andy Jones – University of East Anglia
Roger Mackett – University College London
Simon Griffin – University of Cambridge
Status
Completed.
Unit role
Unit led study in collaboration with University of East Anglia and University College London. Unit responsible for data.
Sponsors
University of Cambridge
Funding
Initial recruitment and baseline data collection was funded by pump-priming funds from UKCRC via the Centre for Diet and Activity Research (CEDAR). Phases 2, 3 and 4 were funded by a grant from the NIHR Public Health Research programme held by the Unit.
Data sharing
We welcome proposals for projects and aim to make data as widely available as possible whilst safeguarding the privacy of our participants, protecting confidential data and maintaining the reputations of our studies and participants.
Please see our Data Sharing portal for more information.