Developing a 15-minute city: Evaluating urban quality using configurational analysis. The case study of Terni and Matera, Italy

the pandemic and the post-pandemic scenarios pose the question of a radical transformation of cities based on criteria of diversity, density, and proximity to foster inclusion, sustainability, participation, and quality of life. The 15-minute city emerges as a robust concept to inform the adaptation of the urban environment to the post-pandemic scenario. The 15-minute city concept combines the components of density, proximity, diversity, and digitalization to increase residents' access to basic services, favour sustainable modes of transportation, and transform public urban spaces into multifunctional places. The proposed study focuses on the dimensions of density, proximity, and diversity. It develops a set of indicators derived from the configurational analysis to evaluate urban quality in terms of the potential to actualize the 15-minute city concept. The selected areas of study are the cities of Terni and Matera in Italy. The study addresses three issues: i) defining a set of relevant, reproducible, and comparable indicators for measuring density, proximity, diversity, and imageability at the district scale; ii) investigating the influence of distinct urban planning concepts, manifested and reproduced by the configuration of public spaces, on density, proximity, diversity, and imageability; and iii) defining urban scale metrics to measure levels of spatial injustice in terms of unequal conditions of access to basic services. The analysis underlines the gap in terms of access to basic services and imageability among central compact districts and dispersed outer areas. As a result, the case study underlines that the proposed set of indicators is instrumental to understanding the urban environment's potential to meet the needs of urban populations. Moreover, by enabling the identification of inequalities in the distribution of spatial capital, the proposed set of indicators facilitates informed decisions in the context of urban planning.