Territorial Areas for Inter-Municipal Planning. Best practices for the definition of “homogeneous zones” in Italy

The processes of metropolization, which have transformed cities into complex territorial systems characterized by increasing fragmentation and development beyond administrative boundaries, represent a key issue in the scientific and disciplinary debate on intermunicipal governance. These dynamics highlight the need to define criteria for delineating optimal cooperation areas, referred to as homogeneous zones, to enhance coordinated planning efforts. This contribution, framed within a doctoral research project conducted at the Department of Planning, Design, and Technology of Architecture (PDTA), Sapienza University of Rome, analyzes the theoretical and methodological framework for defining intermunicipal cooperation areas. It examines the criteria adopted at both national and European levels for their delineation, with a specific focus on the concept of homogeneous zones. The objective is to understand how intermunicipal planning can overcome the limitations imposed by administrative fragmentation through innovative models of territorial governance. To this end, the research presents a comparative analysis of two Italian case studies: the Emilia-Romagna and Tuscany Regions. Both have developed intermunicipal cooperation strategies but have adopted distinct approaches in defining homogeneous zones for planning purposes. The comparative analysis highlights the key role that these territorial areas play in intermunicipal planning, promoting a more integrated and strategic territorial management. By responding to local specificities and ongoing socio-economic transformations, homogeneous zones emerge as an essential tool for fostering effective and adaptive governance models.