This article is posted with permission from the Congress of the New Urbanism (CNU) and originally appeared in CNU's online journal, Public Square. It is posted for information purposes only. CNU is solely responsible for the article's content.
Market Square in downtown Pittsburgh, the heart of a 15-minute city. Courtesy of Strada.
A theoretical framework based on walking and bicycling sheds makes the 15-minute city more useful to cities and planners.
In a world where cities and towns are geared to automobile travel, “the 15-minute city” is gaining momentum as a planning and transportation concept that focuses more on human-scale access than mobility.
Andres Duany and I have written two essays for Public Square providing a theoretical framework for the 15-minute city (defining the concept by applying specific walking and bicycling sheds). As recent research has shown, the 15-minute city is particularly important for low-to-moderate income residents who depend on the cost savings from taking fewer automobile trips.
Two critiques of the theoretical framework need to be addressed. First, some critics think the “15-minute city” doesn’t meaningfully add to urban planning knowledge and it should be ignored. Second, some proponents argue that the 15-minute city doesn’t need further defining and should be left alone, as previously (and vaguely) described.
Before I address these criticisms, a bit of history is needed: Carlos Moreno, professor at the Sorbonne in Paris, is credited with coining the term in 2016, but the concept itself is decades old. It was employed by cities like Melbourne, Australia, and Portland, Oregon, as the “20-minute neighborhood.” The publication that I founded, New Urban News, published a story about Portland's use of this idea in 2008. Moreno later renamed it “the 15-minute city,” a term that has stuck. Moreno’s nomenclature is more accurate (the scale is closer to a city than a neighborhood).
The professor also refers to “chrono-urbanism,” or urban planning based on the metric of time, which has been part of new urbanist thinking since the 1980s. During that decade, new urbanists began to employ the “5-minute walk” to measure the scale of pedestrian sheds—a quarter mile from center to edge of mixed-use neighborhoods. Similarly, new urbanists have used a half-mile pedestrian shed (10-minute walk) as a planning tool around rail transit stations.
From the Lexicon of the New Urbanism, diagrams that use 5-minute and 10-minute walk sheds.
In a paper published in Smart Cities journal in January 2021, Moreno cites many planning theorists who have been influential to, or involved in, New Urbanism—Jane Jacobs, Christopher Alexander, Duany, Nikos Salingaros, William Whyte, Project for Public Spaces, and Jan Gehl. “So essentially, Moreno is advocating New Urbanism,” concludes Laurence Aurbach, author of A History of Street Networks: From Grids to Sprawl and Beyond.
New urbanists could therefore argue the 15-minute city is just another term for what they have been advocating all along. Yet there are good reasons why new urbanists shouldn’t ignore the 15-minute city.
At a time when the 15-minute city is rapidly taking hold as a land-use term, major plans will be based on the idea. To the extent that people are employing the concept in planning, practitioners and public officials need a coherent way to explain and implement it. As one sustainability executive notes, cities define the 15-minute city in widely divergent ways, leading to confusion.
“The ’15-minute city’ is a constant source of discussion,” notes Brian Marion, VP of ClearWorld, in a LinkedIn post. “Providing residents (and tourists) with everything they need to thrive right outside their doorstep offers countless benefits, from the social to the environmental, but its actual enactment proves to be a challenge. The logistics, practicalities, and designs of the 15-minute city vary wildly from city to city, leading to many misunderstandings of what is necessary for its development. Additionally, these plans must be rooted in a deeper knowledge of the needs of individuals, beginning with a human element instead of simply tech advancement.” New urbanists could bring their knowledge of “the human element” to improve 15-minute city implementation.
Also, the 15-minute city could expand the New Urbanism toolbox. Although the 15-minute city is a buzzword, it also has substance. As Duany and I argue, the 15-minute city facilitates regional planning and, when used as we suggest, maintains a fine-grained diversity in neighborhoods. Urbanists need a way of organizing plans on a scale between the 5-minute walk (which has a similar size everywhere) and the metropolitan region (which varies in scale and is often enormous).
The 15-minute city is a useful tool to analyze and plan regions and subregions, because the concept introduces larger planning sheds with measurable sizes that can be organized as diverse, accessible places. As Duany and I wrote: “The 5-minute walk remains important but requires the 15-minute city comprised of several neighborhoods nested together, coalescing at a scale that is able to meet all of people’s daily and weekly needs.”
The three principal kinds of sheds that we identify in the 15-minute city—the 5-minute walk, the 15-minute walk, and the 15-minute bicycle ride—are radically different in scale and each includes a hierarchy of uses. Each shed must have sufficient diversity—otherwise racial, class, and other kinds of segregation will likely result.
In other words, new urbanists should apply more rigorous spatial analysis to the 15-minute city, using human-scale transportation sheds—rather than dismiss the concept.
Some planners don’t think it needs defining, however. As one British transportation planner put it in response to our first essay: “Personally, I don't think the concept needed defining, as Professor Carlos Moreno in Paris has already done that very clearly.”
That planner points to Moreno’s six functions of uses needed in the 15-minute city: Living (housing), working (employers), supplying (food and other goods), caring (health services), learning (education and cultural facilities), and enjoying (recreation and leisure).
But that definition doesn’t clarify the concept much, because there is a great variety in each category, each use demanding a different planning approach. For example, where should various kinds of educational facilities, from elementary schools to universities, be planned within the 15-minute city? When measuring the scale of the 15-minute city—which Moreno doesn’t do—the area inside could be larger than 20 square miles. Unless planners are careful about providing diversity throughout the 15-minute city, uses and people could easily be segregated in an area that big. The theoretical framework that we propose solves the problem through a better analysis of human-scale transportation sheds. “These sheds range from the neighborhood to the regional scale, with every level requiring a diversity of people and activities,” Duany and I explain.
Moreno elucidates his rather loose approach: “It is noteworthy that while the concept of ‘chrono-urbanism’ may seem arbitrary for some—e.g., why 15 min and not 17 min?—this concept is not rigid in nature and is proposed with the intent to be tailored to individual cities based on both their morphology and specific needs and characteristics. . . . Indeed, on this matter, there had been other concepts such as 20-min cities and 30-min cities, but the bottom line in all of those is the need to underline that proximity-based planning is key in sustaining quality of life and in providing for the basic urban functions.”
And yet the 15-minute city does need to be defined with a degree of rigor to make it implementable, and prevent the kind of segregation typically found in modern metropolises. The implementation doesn’t need to be rigid. There’s a difference between rigorous, on the one hand, and rigid, on the other. The rigor involves defining the theoretical areas of the sheds, establishing a hierarchy of uses within each, and measuring the diversity at every scale.
The distances are radically different for different modes of transportation within the 15-minute city, such as walking, bicycling, or small electric vehicles. Speaking of the latter, technology and micro-mobility are big topics among proponents of the 15-minute city. While the concept should be built around human access, technology nevertheless plays an important role.
For example, the 15-minute city is the perfect scale to apply many new high-tech mobility systems, which allow households to get by without a car. A public-private partnership in Memphis, for example, launched Groove On-Demand in 2021, designed by the innovative transportation company Via. This car-share system allows anyone to ride within a 15-square-mile area near downtown for $1.25 (extra passengers, senior citizens, students, and disabled, ride for as little as 50 cents). Groove On-Demand works like Uber, but at a tenth of the price or less (it is subsidized and the service is likely slower). It is no coincidence, however, that the scale matches the 15-minute city in Memphis, covering an area that is within three miles north, south, and east of downtown. Without the proximities of the 15-minute city, such a program would probably be too costly or otherwise unfeasible.
With sufficient analysis, the 15-minute city can be very useful for cities. We need a theoretical framework that is based on the metric of time, applying to areas that are larger than individual neighborhoods, to help organize metropolitan regions. In clarifying the definition, new urbanists will find that the 15-minute city adds to their toolbox in a meaningful way, and doing so will help cities to apply the concept successfully.