1. History

The 15-minute city is derived in part from historical concepts of proximity and walkability, such as Clarence Perry's controversial neighborhood unit and the model Jane Jacobs laid out in The Death and Life of Great American Cities, which Moreno cited as inspiration for his modern conception first published in 2016.^[1][2][3]

Anne Hidalgo, the Mayor of Paris, included the 15-minute city in her 2020 re-election campaign.^[4]

The global COVID-19 pandemic accelerated the consideration and implementation of the 15-minute city, in response to the climate crisis and the urban effects of the COVID-19 pandemic crisis.^[2] The C40 Cities Climate Leadership Group, in July 2020, published a framework for cities to "build back better" with the 15-minute concept, referring specifically to plans implemented in Milan, Madrid, Edinburgh, and Seattle after COVID-19 outbreaks.^[5] The C40 Cities Climate Leadership Group report highlighted the importance of inclusive community engagement through mechanisms like participatory budgeting, and adjusting city plans and infrastructure to encourage dense, complete communities.^[5]

In April 2020 a proposal for radical change in the organisation of the city, the Manifesto for the Reorganisation of the City after COVID19, was published in Barcelona. It is based on four key elements: Reorganisation of mobility, (Re)naturalisation of the city, Decommodification of housing, Degrowth^[6][7][8]

2. Research Models

The 15-minute city^{[2][9][10][11]} is a proposal for developing a polycentric city, where density is made pleasant, where proximity is vibrant and where social intensity is real.

While Carlos Moreno first proposed the 15-minute city in 2016, other authors have proposed similar but different models within in the realm of "chrono-urbanism".^[2]

2.1. Moreno and the 15-Minute City

Moreno et al., in their 2021 article, introduce the 15-minute city concept as a way to ensure that urban residents can fulfil six essential functions (living, working, commerce, healthcare, education, and entertainment) within a 15-minute walk or bike from their dwellings.^[2] The 15-minute city framework of this model has four components: density, proximity, diversity, and digitalization.^[2]

Moreno et al. cite the work of Nikos Salingaros, who posits that there exists an optimal density for urban development which would encourage local solutions to local problems.^[2][12] The authors discuss proximity in terms of both space and time, and argue that a 15-minute city would decrease both the time and space necessary for activity by increasing proximity to services.^[2] Diversity in this 15-minute city model refers to both mixed-use development and multicultural neighborhoods, both of which Moreno et al. argue would improve the urban experience and increase community participation in the planning process. Digitalization is a key aspect of the 15-minute city derived from smart cities. Moreno et al. argue that the Fourth Industrial Revolution has reduced the need for commuting because of access to technology like virtual communication and online shopping. Moreno et al. conclude by stating that these four components, when implemented at scale, would form an accessible city with a high quality of life.^[2]

2.2. Weng and the 15-Minute Walkable Neighborhood

Weng et al., in their 2019 article using Shanghai as a case study, propose the 15-minute walkable neighborhood with a focus on health, specifically non-communicable diseases.^[13] The authors posit the 15-minute walkable neighborhood as a way to improve health of residents, and documented existing disparities in walkability within Shanghai. The authors found that rural areas on average are significantly less walkable, and that areas with low walkability tend to have a higher proportion of children.^[13] Compared to Moreno et al., the authors focused more on health benefits of walking and differences in walkability and usage across age groups.^[2][13]

2.3. Da Silva and the 20-Minute City

Da Silva et al., in their 2019 article using Tempe, Arizona, as a case study, propose the 20-minute city, 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 accessibility varies with geographic area. Compared to Moreno et al., the authors focused more on accessibility within the built environment.^[14]

3. Implementations

3.1. Africa

Lagos, Nigeria, converted schools 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.^[15]

3.2. Asia

Singapore's Land Transport Authority in 2019 proposed a 2040 Master Plan that included the goals of "20-minute towns" and a "45-minute city".^[16]

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 China cities, like Baoding and Guangzhou, to varying degrees.^[17]

The Standard for urban residential area planning and design (GB 50180-2018), a national standard which 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 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.^[18]

3.3. Europe

Example of bike lane in Paris. https://handwiki.org/wiki/index.php?curid=1890754

Paris Mayor Anne Hidalgo introduced the 15-minute city concept during her 2020 re-election campaign, and began implementing the concept during the COVID-19 pandemic. For example, school playgrounds have been converted to parks after hours, while the Place de la Bastille and other squares have been revamped with trees and bicycle lanes.^[19]

Cagliari, a city on the Italian island of Sardinia, began a municipal strategic plan for revitalizing the city and improving walkability.^[20] The city actively sought public feedback through a participatory planning process, as described in the Moreno model. A unique aspect of the plan calls for repurposing public spaces and buildings that no longer were being used, relating to the general model of urban intensification.^[20]

3.4. North America

Portland, Oregon , in 2012, developed a plan for complete neighborhoods within the city, which are aimed at supporting youth, providing affordable housing, promoting community-driven development, and commerce in historically underserved neighborhoods.^[21][22] 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.^[22] 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.^[22]

3.5. South America

Bogotá, Colombia in March 2021, implemented 84 kilometers of bike lanes to encourage social distancing during the COVID-19 pandemic.^[23] This expansion complemented the Ciclovía practice that originated in Colombia in 1974, where bicycles are given primary control of streets.^[23] The resulting bicycle lane network is the largest of its kind in the world.^[24]

3.6. Oceania

Melbourne developed Plan Melbourne 2017-2050 to accommodate growth and combat sprawl.^[22][25] The plan contains multiple elements of the 15-minute city concept, including new bike lanes and the construction of "20-minute neighborhoods."^[26][27]

4. Implications

The 15-minute city, with its emphasis on walkability and accessibility, has been put forth 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.^[22]

The 15-minute city also emphasizes social infrastructure like schools, parks, and complementary activities to maximize urban functions for residents.^[22]

The 15-minute city's focus on green space may promote positive environmental impacts, such as increasing biodiversity and preventing invasive species.^[22]

5. Critiques

While many cities have implemented policies that resemble the 15-minute city concept, there remains disagreement over whether the model benefits residents. Critics have pointed out that the creation of dense, walkable cores, like a 15-minute neighborhood, often lead to gentrification and displacement.^[22] Furthermore, price increases, like those which lead to gentrification, could be most harmful to marginalized groups like people with disabilities, forcing move-outs.^[28]

Similarly, as the origin of the idea is largely European, critics have argued that implementation of the model could be colonialist and perpetuate harms to marginalized communities.^[29]

In addition, critics have noted that models are not universal, as cities with less urban sprawl, like those in Europe, are more likely to implement the concept than cities with lots of sprawl, like those in Asia and North America.^[19] Notable exceptions include Chengdu, which utilized the 15-minute city concept to curb sprawl, and Melbourne, where Sally Capp, the Lord Mayor of Melbourne, stressed the importance of public transit in expanding the radius of the 15-minute city.^[26]