Exploring the Influence of Changes to the Built Environment on Walking Behaviour: A Natural Experiment within a University Campus in Hong Kong

Background: Previous studies testing the association between the built environment and walking behaviour have been largely cross-sectional and have yielded mixed results. This study reports on a natural experiment in which changes to the built environment were implemented at a university campus in Hong Kong. Longitudinal data on walking behaviours were collected using surveys, one before and one after changes to the built environment, to test the influence of changes in the built environment on walking behaviour.;Experimental design: Changes to land use, campus bus services, pedestrian network, and population density were collected from campus maps, the university developmental office, and field surveys. Motivational data towards walking were collected at baseline in March 2012 (n=198) and after changes to the built environment from the same cohort of subjects in December 2012 (n=169) using a Theory of Planned behaviour (TPB) based questionnaire. Walking behaviours were objectively measured by a walking-oriented diary in the two points of survey.;Methods: Geographic information system (GIS) was used to map the changes to the built environment and walking behaviours. Walking outcomes were measured in terms of: i) walking distance, ii) destination-oriented walking, and iii) walked altitude range. Multivariate linear regression models were used to test for associations between changes to the built environment and walking behaviours. A walking accessibility measure that allows comparison of perception and reality of walking in this hilly community is developed by GIS. Structural equation modelling is used to test the causal relationship between the motivational factors, including the salient beliefs, attitude, perceived behaviour control (PBC), subjective norm (SN), intention, and walking outcomes.;Results: We found that i) changes to the built environment lead to changes in walking behaviours. Specifically, Greater pedestrian network connectivity predicted longer walking distances and an increased likelihood of walking as a means of transportation. The increased use of recreational (vs. work) buildings, largely located at mid-range altitudes, as well as increased population density predicted greater walking distances. Having a greater density of work buildings at lower altitudes deceased subjects' walked altitude range, while having more bus services and a greater population density encouraged people to increase their walked altitude range;;ii) We developed a practical walking accessibility measure, which was used to visualize the geography of the difference between the perception and reality of walking in this hilly environment for use by urban planners and public health practitioners. We practically addressed the issues in calculating accessibility measures in the present context arise primarily from problems with data quality, three-dimensional pedestrian network modelling and the adequacy of accessibility methods for describing and predicting walking behaviour; and.;ii) We found that PBC and attitude were the major determinants of intention, while SN did not exert a significant effect in prediction of intention and walking behaviour. Compared with the baseline survey, PBC has an increased effect on the intention in the follow-up survey. This study partially supports the proposed causal nature of the TPB as a framework for investigating the influence of changes to the built environment on walking behaviours.