15-minute city
A 15-Minute City is a residential urban concept in which most daily necessities can be accomplished by either walking or cycling from residents' homes. The concept was popularized by Paris mayor Anne Hidalgo and inspired by French-Colombian scientist Carlos Moreno. 15-minute cities are built from a series of 5-minute neighborhoods, also known as complete communities or walkable neighborhoods. The concept has been described as a "return to a local way of life." History. The 15-minute city concept is derived from historical ideas about proximity and walkability, such as Clarence Perry's controversial  neighborhood unit. As inspiration for the 15-minute city, Moreno cited Jane Jacobs's model presented in "The Death and Life of Great American Cities". Paris's mayor Anne Hidalgo included a plan to implement the 15-minute city concept during her 2020 re-election campaign. The climate crisis and global COVID-19 pandemic combined to accelerate consideration and implementation of the 15-minute city. In July 2020, the C40 Cities Climate Leadership Group published a framework for cities to "build back better" using the 15-minute concept, referring specifically to plans implemented in Milan, Madrid, Edinburgh, and Seattle after COVID-19  outbreaks. The C40 Cities Climate Leadership Group report highlights the importance of inclusive community engagement through mechanisms like participatory budgeting and adjusting city plans and infrastructure to encourage dense, complete, overall communities. A manifesto published in Barcelona in April 2020 proposed radical change in the organization of cities in the wake of COVID-19, and was signed by 160 academics and 300 architects. The proposal has four key elements: reorganization of mobility, (re) naturalization of the city, de-commodification of housing, and de-growth. Research Models. The 15-minute city is a proposal for developing a polycentric city, where density is  made pleasant, one's proximity is vibrant, and social intensity (a large number of productive, intricately linked social ties) is real. Carlos Moreno first proposed the 15-minute city in 2016. Others have proposed similar but varying models within the field of "chrono-urbanism". Moreno and the 15-minute city. Moreno's 2021 article introduced the 15-minute city concept as a way to ensure that urban residents can fulfill six essential functions within a 15-minute walk or bike from their dwellings: living, working, commerce, healthcare, education and entertainment. The framework of this model has four components; density, proximity , diversity and digitalization. Moreno cites the work of Nikos Salingaros, who theorizes that an optimal density for urban development exists which would encourage local solutions to local problems. The authors discuss proximity in terms of both space and time, arguing that a 15-minute city would reduce the space and time necessary for activity. Diversity in this 15-minute city model refers to mixed-use development and multicultural neighborhoods, both of which Moreno and others argue would improve the urban experience and boost community participation in the planning process. Digitalization is a key aspect of the 15-minute city derived  from smart cities. Moreno and others argue that a Fourth Industrial Revolution has reduced the need for commuting because of access to technology like virtual communication and online shopping. They conclude by stating that these four components, when implemented at scale, would form an accessible city with a high quality of life. Larson and the 20-minute city. Kent Larson described the concept of a 20-minute city in a 2012 TED talk and his City Science Group at the MIT Media Lab has developed a neighborhood simulation platform to integrate the necessary design, technology, and policy interventions into “compact  urban cells.” In his “On Cities” masterclass for the Norman Foster Foundation, Larson proposed that the planet is becoming a network of cities, and that successful cities in the future will evolve into a network of high-performance, resilient, entrepreneurial communities. Weng and the 15-minute walkable neighborhood. Weng and his colleagues, in a 2019 article using Shanghai as a case study, proposed the 15-minute walkable neighborhood with a focus on health, and specifically non-communicable diseases. The authors suggest that the 15-minute walkable neighborhood is a way to improve the health of residents, and they document existing  disparities in walkability within Shanghai. They found that rural areas, on average, are significantly less walkable, and areas with low walkability tend to have a higher proportion of children. Compared to Moreno et al., the authors focused more on the health benefits of walking and differences in walkability and usage across age groups. Da Silva and the 20-minute city. Da Silva et al., in their 2019 article cite Tempe, Arizona, as a case study of an urban space where all needs could be met within 20 minutes by walking, biking, or transit. The authors found that Tempe is highly  accessible, especially by bike, but that accessibility varies with geographic area. Compared to Moreno et al., the authors focused more on accessibility within the built environment. Implementations. Africa. Lagos, Nigeria, converted schools that were closed due to the COVID-19 pandemic into food markets to prevent panic buying. The program also decreased commute times and shored up food supplies within communities. Asia. Singapore's Land Transport Authority in 2019 proposed a by 2040 a master plan that included the goals of "20-minute towns" and a "45-minute city". China. The 2016 Master Plan for Shanghai called for "15-minute community  life circles," where residents could complete all of their daily activities within 15 minutes of walking. The community life circle has been implemented in other Chinese cities, like Baoding and Guangzhou. The "Standard for urban residential area planning and design" (GB 50180–2018), a national standard that came into effect in 2018, stipulates four levels of residential areas: 15-min pedestrian-scale neighborhood, 10-min pedestrian-scale neighborhood, 5-min pedestrian-scale neighborhood, and a neighborhood block. Among them, "15-min pedestrian-scale neighborhood" means "residential area divided according to the principle that residents can meet their material, living and cultural  demand by walking for 15 minutes; usually surrounded by urban trunk roads or site boundaries, with a population of 50,000 to 100,000 people (about 17,000 to 32,000 households) and complete supporting facilities." Chengdu, to combat urban sprawl, commissioned the "Great City" plan, where development on the edges of the city would be dense enough to support all necessary services within a 15-minute walk. Europe. Paris Mayor Anne Hidalgo introduced the 15-minute city concept in her 2020 re-election campaign and began implementing it during the COVID-19 pandemic. For example, school playgrounds were converted to parks after hours, while  the Place de la Bastille and other squares have been revamped with trees and bicycle lanes. Cagliari, a city on the Italian island of Sardinia, began a strategic plan to revitalize the city and improve walkability. The city actively solicited public feedback through a participatory planning process, as described in the Moreno model. A unique aspect of the plan calls for re-purposing public spaces and buildings that were no longer being used, relating to the general model of urban intensification. North America. In 2012, Portland developed a plan for complete neighborhoods within the city, which are aimed at supporting  youth, providing affordable housing, and promoting community-driven development and commerce in historically under-served neighborhoods. Similar to the Weng et al. model, the Portland plan emphasizes walking and cycling as ways to combat non-communicable diseases like obesity and stresses the importance of the availability of affordable healthy food. The Portland plan notably calls for a high degree of transparency and community engagement during the planning process, which is similar to the diversity component of the Moreno et al. model. South America. Bogotá, Colombia in March 2021, implemented 84 kilometers of bike lanes to encourage social distancing during the  COVID-19 pandemic. This expansion complemented the Ciclovía practice that originated in Colombia in 1974, where bicycles are given primary control of the streets. The resulting bicycle lane network is the largest of its kind in the world. Oceania. The city of Melbourne, Australia developed Plan Melbourne 2017–2050 to accommodate growth and combat sprawl. The plan contains multiple elements of the 15-minute city concept, including new bike lanes and the construction of "20-minute neighborhoods." Implications. The 15-minute city, with its emphasis on walkability and accessibility, has been put forward as a way to better serve groups of people  that have historically been left out of planning, such as women, children, people with disabilities, and the elderly. Social infrastructure is also emphasized in order to maximize urban functions such as schools, parks, and complementary activities for residents. There is also a large focus on access to green space, which may promote positive environmental impacts such as increasing urban biodiversity and helping to protect the city from invasive species. Studies have found that increased access to green spaces can also have a positive impact on the mental and physical health of a city's inhabitants, reducing stress and negative emotions , increasing happiness, improving sleep, and promoting positive social interactions. Urban residents living near green spaces have also been found to exercise more, improving their physical and mental health.