Abstract
Polycentrism has become the keystone in a major number of regional and urban policies, since it has been seen as a sustainable and equilibrated urban model. In this paper, the problem has been focused in case study the biggest metropolitan areas in Spain and pretends test whether polycentric urban growth does effectively reduce land consumption and travel-to-work journeys, protecting in this way agricultural and forest areas around cities and at the same time reducing energy and air emissions produced by cars. The methodology used has been departed from land-use, transport and census data, and using ArcGIS and TransCAD a group of spatial indicators is calculated and introduced in a family of regression models, where explained variables are per capita land consumption and excess commuting respectively. The results suggest that polynucleation has little effect both in the reduction of land consumption and excess commuting. On the contrary, other variables associated to urban form do highly influence land and mobility patterns, such as fragmentation of urban fabrics, job ratio balance, and the diversity of economic activities and housing offer. Such conclusions may shed light in the design of urban policies, and focus the attention on the definition of small-scale urban variables instead of structural ones at metropolitan scale.