Climate Advice Columnist
November 28, 2023 at 6:30 a.m. EST
But the 15-minute city — as it is often understood — has inspired fierce pushback. In its journey from urban planning circles to the public arena, some have falsely claimed it will imprison people within a 15-minute radius of their homes (it’s about convenience and freedom, advocates argue, not isolation). Some urban planners object to the idea. They say that not everyone’s workplace can be within a 15 minute walk, shrinking a metropolitan area’s job market.
But amid smoldering housing and climate crises, the 15-minute-city concept offers a way out of both, reducing our dependence on cars to go about our daily lives and freeing us to spend our time as we choose. To realize this, we need to look to an unlikely place: the first suburbs.
Throughout recorded human history, less than 5 percent of people lived in cities. But in the relative blink of an eye, this situation reversed. People began leaving the countryside in droves during the Industrial Revolution. By 2008, the urban population had eclipsed the rural one. The gap continues to widen. Seventy percent of the world’s population is expected to live in cities by 2050.
Urban migration has supercharged human prosperity: An estimated 80 percent of the world’s economic activity now occurs in cities. This has reduced per capita environmental impact in some high-income nations. City dwellers emit as much as 20 percent less compared to their rural counterparts, largely thanks to more efficient transport, heating and cooking, according to studies in the United Kingdom, Finland, Austria and Switzerland.
But cities are staggering under their success.
Congestion and unaffordability are pushing people from many cities into expensive housing in far suburbs or exurbs. Vehicles have been the leading source of greenhouse gases in the United States since 2017.
Few things exemplify this trajectory better than commuting in the United States.
American commuters spent an average of about an hour each day driving to work in 2019, the vast majority alone, up from 44 minutes in 1980 (the pandemic put only a slight dent in these numbers). Few enjoy it. When 900 Texas women were asked to rate their feelings about daily activities, the morning commute came in dead last — after work and household chores. Longer commute times have also been associated with more stress, poorer mental health and lower job and leisure time satisfaction — the equivalent of a 20 percent pay cut, according to a 2020 study in the journal Transportation.
The response has been the 15-minute city.
The rise of the 15-minute city
Conceived in 2016 by Carlos Moreno, the 15-minute city imagines putting “humans and their well-being as the main purpose of urban organization,” Moreno, an urbanist and professor at the Sorbonne University in Paris, told The Washington Post in March. The idea is “to promote sustainability and health by reducing car dependency and increasing physical activity,” primarily through walking, biking and mass transit.
This decentralized urban planning model has become a rallying cry for politicians and urban activists around the world fed up with exclusive single-use zoning, car-centric development and homes segregated from work, retail shopping and other amenities.
Yet the discussion about 15-minute cities obscures a central tension at the heart of the idea: How can all of us live within 15 minutes of all amenities and jobs in cities housing millions of people?
“It’s not a very controversial idea in urban planning that it’s better when you can reach things close by in a city,” says David Zipper, a visiting fellow at the Harvard Kennedy School studying transportation policy. “But you can take it too far. … Everyone can live and work within 15 minutes of where they want to go? That’s just not how things work.”
This tension has shaped cities for millennia. Known as Marchetti’s constant, after Cesare Marchetti, the Italian physicist who identified it in 1994, it describes a nearly universal rule of human behavior: People tend to travel no more than one hour per day. This constant has defined the dimensions of cities since they arose about 10,000 years ago.
Ancient villages tended to grow no bigger than about five kilometers, a radius walkable in half an hour, reports Quartz. Today, the average one-way commute in the age of automobiles remains remarkably consistent in the United States (27.6 minutes), Canada (26.2) and the U.K. (29.5). No matter the speed or form of transportation, humans will travel 30 minutes for daily trips.
For cities, this number is critical because it defines how big their job markets can get.
“The welfare of cities is dependent on their labor markets,” Alain Bertaud, an urban planner at New York University’s Marron Institute, wrote in an influential 2014 essay. “The larger the market, the more innovative and productive the city.” By putting as many people as possible near desirable jobs, those who live in low-income communities can reach additional employment opportunities, research has shown.
Without this dynamic, as a tour of America’s Rust Belt reveals, you get decay. “Without a functioning labor market there is no city,” Bertaud writes. The main objective of urban planning should be mobility, he argues, preventing commuting time from rising as the size of the labor market increases, and freeing people to spend their time elsewhere.
A tale of two kinds of trips
Does this doom the 15-minute city? Not necessarily, says Adie Tomer, an urban economics and infrastructure policy expert at Brookings Metro.
But we need to make a key distinction. “There are really two kinds of trips: the commute and everything else,” says Tomer. “There might be one perfect job for you in that [city’s] labor market. But that’s at a completely different proximity than you need for your bakery, grocery store or daily activities.”
Amenities are relatively interchangeable. Almost any pharmacy or pizza place will do. But only a few companies may want to hire you in a city.
From an urban economist’s perspective, the perfect 15-minute city fosters local businesses and amenities 15 minutes (or less) to optimize free time and quality of life. It maximizes economic opportunity, ideally by many modes of transportation, within a 30-minute radius of people’s homes. “The 15-minute city vision is really one of consumption,” Zipper says.
In the United States, the challenge is that communities have been built around the personal vehicle. Whereas life once revolved around being relatively close to things, virtually everything now involves getting behind the wheel. The average American traveled 40 miles per day in 2017, up from 19.5 miles in 1969, according to Tomer’s research.
“We are so deep in the suburbanization mode that the majority of trips in the U.S. are already under two miles, but we use our vehicles for them at disproportionate rates compared to almost any other country,” Tomer says. “Americans have been hiding both the social and household costs of this model we’ve built.” The United States now ranks highest among its peers for roadway deaths, per capita greenhouse gas emissions, miles traveled and infrastructure costs.
Luckily, the United States has already built 15-minute cities across the country: the first suburbs.
Why you might already be living in a 15-minute city
In the 1890s, the first streetcar suburbs emerged: Cleveland’s Shaker Heights, Atlanta’s Inman Park, Somerville, Mass., outside Boston and Philadelphia’s Main Line are among the most famous, with electric streetcars ferrying workers to and from urban jobs. It was the dominant way American cities grew until the 1930s.
What helped these older, inner-ring communities thrive was a core of mixed-use development — high and low-density housing alongside shops and other services — next to fast, affordable transportation. The dominance of the automobile, and the 1926 Supreme Court approval of more sweeping zoning ordinances created the distant suburbs we know today.
But Tomer thinks the first suburbs are these 15-minute cities in waiting.
In his study Building for Proximity, Tomer and his colleague Caroline George studied Americans’ daily trips in the 110 largest U.S. metro areas using a mix of information, including cellphone geolocation data and credit card transactions.
People living within three miles of what he calls “activity centers” (commercial strips, but also malls, museums, libraries, shops, schools and restaurants), exhibited radically reduced daily travel.
Those living near at least five activity centers were estimated to travel 14,500 fewer annual miles, emit one-third less carbon and save more than $1,000 in transportation expenses each year compared to those living seven miles away, the distance a typical American must travel for shopping and recreational activities.
America’s first suburbs already enjoy multifamily residential developments, neighborhood stores, shops and cultural institutions and efficient access to downtown jobs by car, public transit and biking or walking.
“These often are not 15-minute neighborhoods yet, but they have the bones for it,” he says. “You just have to do a little work.”
Many of the changes needed are in the hands of local communities.
Take parking. Eliminating parking requirements has removed the need for sprawling, underutilized parking lots for businesses, apartments and multifamily housing, a crucial step to realizing the 15-minute ideal. Since 2017, at least 35 cities or towns in North America have eliminated citywide parking mandates, more than one-third of them in the past year or so.
Here’s how 15-minute cities could rise near you, if you have the ear, and the votes, of your city council.
Build more housing, especially along busy corridors: First suburbs perfected this 100 years ago — and could do so again. By creating more places to live immediately next to hubs of commercial buildings, retail, food, market districts and, ideally, mass transit, both people and businesses benefit from the reduced time needed to get around. One of the best ways to do this is to let people build and live where they would like.
And that would require …
Loosening up zoning laws: Many Parisians already live in a 15-minute city (or a five-minute one) despite prescriptive zoning. Paris’s 40 square miles are served by an estimated 1,180 bakeries and 516 butcher shops, according to one government survey.
“The abundance and variety of bakeries are not due to meticulous municipal planning but to market mechanisms,” writes NYU’s Bertaud. “If Parisians were to prefer herring to croissants for breakfast in the future, the market would adjust, and herring merchants will gradually replace the bakeries without any ‘redesign’ of Paris.”
Yet in the United States, strict zoning laws have become de rigueur almost everywhere. With fewer rules on density and commercial uses near homes, many of us could already live in neighborhoods more like Paris and reach amenities by taking a short stroll. An analysis of New York neighborhoods found places with more permissive commercial zoning in 1961 enjoy more local trips today. The dominance of single-family zoning, even next to transit hubs, means fewer people have the choice to live near cities and amenities.
Protect all forms of transportation: We design cities to quickly and efficiently move cars, not necessarily people. By using little more than some paint and lane dividers for pedestrians, bikes or scooters, we could significantly speed up how fast we move around our neighborhoods. “I’m not anti-car,” says Tomer, whose family owns two. “I’m anti-designing communities solely or primarily for the car.”
This is one of the few instances where the “Field of Dreams” model of infrastructure works, according to Carlo Ratti, an architect and engineer who directs the Senseable City Lab at MIT. His study of anonymized cellphone location data for 40 million Americans showed “people automatically construct their lifestyles around 15-minute walks if amenities such as parks and grocery stores are available within that radius,” he writes. “In other words, if we build it, they will come.”