Does polycentrism reduce land consumption? an analysis for the biggest metropolitan systems in Spain

Abstract

The bid rent theory is the paradigm that supports the so called urban economics. According to such a theory, the accessibility to centres and subcentres is correlated to land rent, and consequently to urban density. By means of a substitution effect developers build dense structures in central areas where land is expensive and conversely they build low rise buildings in peripheral land cheap zones. Nonetheless, urban density is not only associated to accessibility but to environmental externalities, income level, the nature of activities and topographic constrains of the terrain. In this paper we report the results of an analysis carried out in the biggest metropolitan areas in Spain regarding the impact of accessibility on urban density .The results suggest that after controlling for proximity to CBD, environmental amenities, and other attributes that theoretically impact on urban density, proximity to sub centres does fail to have a significant impact on per capita land consumption beyond the subcentre itself. These results call into question the hypothetical environmental advantages that policy makers have seen on the promotion of polycentricity, and the necessity to stress the control on other variables affecting zoning conditions