Ebbs and flows of metropolitan authorities: Supra-local spatial planning and impact on land-use patterns

In this study, I propose an analytical approach to describe the institutional trajectory of metropolitan authorities by using theory-based institutional models that, like ‘ebbs’ and ‘flows’, alternate over time. By employing a comparative, qualitative case-based approach, I empirically validated this analytical approach by reconstructing the divergent institutional trajectories of the metropolitan authorities in Barcelona, Spain and Milan, Italy over a period of 70 years. Furthermore, I examine to what extent the different institutional trajectories of both metropolitan authorities have had an indirect impact on land-use patterns by comparing longitudinal datasets (1950s-2010s) at different territorial scales. Results show that the different institutional models characterizing both metropolitan authorities cannot be clearly associated with a higher or lower proportion of urbanized areas. Rather, findings suggest that it is the inter-mediating role that metropolitan authorities routinely perform that can promote efficient land-use development and sustainable use of land as a scarce resource (equifinality).