The interaction of spatial planning and transport policy: A regional perspective on sprawl

Urban sprawl is caused by the interlinkage of spatial planning and transport characteristics. However, there are only a few approaches that quantify the cross-impacts of policy options in these two spheres. The purpose of this paper is thus a combined regional analysis of spatial planning instruments and transport policy, with a special emphasis on urban-rural diversities. We link a multi-region computable general equilibrium model that incorporates elements of the new economic geography with a transport forecast model. The general equilibrium model illustrates residential choice between urban and peripheral regions, while the transport model depicts the transport implications thereof. Our results suggest that transport policy is obviously effective in addressing transport externalities, while it would have to be set at a politically infeasible stringency to have an effect on residential patterns. As for spatial planning instruments (i.e., expanding housing supply in central regions or limiting it in peripheral regions), we find a strong potential to influence residential choice and hence urban sprawl. Along this line, spatial planning instruments do have a small but still significant impact on reducing transport volume and number of trips. This impact can be enhanced by a policy promoting public transport.