Exploring the 15-minutes city: the metropolitan context of Oporto

It is easy to understand why the idea of a 15-minutes city, providing most everyday amenities within 15-minutes travel time, has become so appealing to city officials and citizens in the last decades, and with particular strength, in the last few years following the COVID-19 pandemic. The explicit reduction of both travel distance and time are, in themselves, tantalizing for societies in need of coping with major challenges, such as, global warming, sustainable development, car-dependent cities, lack of quality urban spaces, and quality of life. Regardless, such prescriptive strategy seems to be at odds with less dense urban environments found in sprawl, the majority of suburban development and even some urban centres. Using the idea of a 15-minutes city as an analytical lens instead of a prescriptive policy, this paper aims to explore the diversity of settings for the 15-minutes city, using a metropolitan area as testbed for its diversity of urban and suburban contexts. Our research explores the diversity of accessibility conditions currently offered at 15-minutes walking time (grouped into typologies), using network-based accessibility measures at the census tract level. Our analysis of the core municipalities of the metropolitan area of Porto revealed 6 main typologies for the 15-minutes city with roughly 18% of the population able to reach all of the considered amenities while 1% has none at 15-minutes walking. Although some areas seem able to move up in the referred typologies through policies such as the ones prescribed by the 15-minutes city concept, others seem unable to make the change. Uniformity does also not necessarily seem desirable for the different urban context encountered. Finally, forcing fashionable concepts, as this one, onto urban areas may come at the expense of the underlying sustainability concerns they were developed to encourage.