Is the decline of active travel to school unavoidable by-products of economic growth and urbanization in developing countries?

Background: Economic growth and urbanization may contribute to the decline of active travel to school (ATS). We aim to explain the change of ATS in China between 1997 and 2011 and to predict the prevalence of ATS in China within the next 30 years using various scenario. Methods: We developed a system dynamics model to study ATS and the model assumes the prevalence of ATS is determined by the dynamic interaction of four exogenous and eight endogenous variables. Results: The simulated prevalence of ATS is roughly consistent with empirical data. Economic development and urban sprawl are more influential than urban design and crime in terms of ATS. Under a relatively reasonable scenario, the prevalence of ATS is projected to decrease from 73% in 2011 to 65% in 2014, and the prevalence of childhood overweight & obesity is projected to increase from 24% in 2011 to 34% in 2041. With the maintaining of economic development grow, to control urban sprawl is the most effective measure to promote ATS and decrease childhood obesity. Conclusions: Overall, the model enabled us to conduct experiments to test the possible effects of changing one or more factors taking into account their dynamic interrelationship, and our study may provide implications for policy intervention.