When Luke Harris takes his daughter to the doctor, he strolls down well-kept streets with “smooth sidewalks and curb cuts [ramps] for strollers at every intersection”. If the weather looks rough or he feels a little lazy, he hops on a tram for a couple of stops.
Harris’s trips to the paediatrician are pretty unremarkable for fellow residents of Zurich, Switzerland; most Europeans are used to being able to walk from one place to another in their cities. But it will probably sound like fantasy to those living in San Antonio, Texas. That’s because, according to new research, 99.2% of Zurich residents live within a 15-minute walk of essential services such as healthcare and education, while just 2.5% of San Antonio residents do.
“Zurich feels extraordinarily walkable to me, coming from the US,” said Harris, a landscape architect from Portland, Oregon. “Most of the things you need are within walking distance – and if they’re not, it’s easy to take public transport.”
Just a tiny fraction of 10,000 cities around the world can be considered “15-minute cities”, according to a study published in the journal Nature Cities on Monday. The researchers used open data to work out the average distance people must walk or bike to reach essential services – such as supermarkets, schools, hospitals and parks – and calculated the proportion of residents who have the necessities at their fingertips.
“When we looked at the results, we were amazed by how unequal they are,” said Matteo Bruno, a physicist at Sony Computer Science Laboratories in Rome and lead author of the study.
The researchers selected 54 cities to explore in detail and found that the most accessible cities were midsize European ones such as Zurich, Milan, Copenhagen and Dublin – all of which had essential services that could be accessed within 15 minutes by more than 95% of residents. At the bottom of the rankings were sprawling North American cities with a high dependency on cars, such as San Antonio, Dallas, Atlanta and Detroit.
Small cities tended to score better but the researchers found that in some big metropolises, such as Berlin and Paris, more than 90% of residents live within a 15-minute walk of essential services.
The authors developed an algorithm to explore how much these cities would have to change to become more accessible. They found Atlanta would have to relocate 80% of its amenities to achieve an equal distribution per resident, while Paris would need to relocate just 10%.
Hygor Piaget, a co-author of the study who grew up in São Paulo, where 32% of people live within a 15-minute walk of essential services, said the study was not a proposal to destroy cities and reallocate their services but a mathematical exercise to get people thinking. “We’re searching for ways to make the lives of most people better,” he said.
The concept of a 15-minute city has been attacked in recent years by conspiracy theorists who see it as a government plot to control movement and restrict freedom. The vitriol has frustrated scientists, urban planners and doctors, who point out that reducing car dependency is a powerful way to help people lead healthier and safer lives.
“The idea of 15-minute cities is not new,” said Piaget. “People who do research on this have been doing it for decades.”
The authors say the study is limited by the quality of the open data, which is patchier in cities outside of Europe and North America, and how practical it is to walk in some cities. Heavy traffic, high crime, bad weather and steep hills may discourage people from walking even geographically short distances.
Natalie Mueller, an environmental epidemiologist at the Barcelona Institute for Global Health (ISGlobal), who was not involved in the study, said there was no “one-size-fits-all” approach that would work for all cities, but that the research could help foster more inclusive and sustainable urban environments.
“By minimising car dependency, encouraging active and public transport and integrating nature-based solutions such as planting trees and expanding green spaces, we can improve urban environmental quality, which directly benefits the health of the population,” Mueller said.
Researchers caution that making a city more accessible is not enough in itself to wean residents away from private cars. The Netherlands boasts some of the best bicycle infrastructure in Europe but has more cars per person than rural countries such as Ireland and Hungary.
In Zurich, where 71% of residents voted in favour of a proposal in 2020 to build 50km of bicycle infrastructure, locals have long grumbled about the lack of bicycle lanes and the threats to cyclists.
“You still see a lot of cars on the street,” said Harris. “In terms of the pedestrian experience, it’s lovely, I truly cannot think of other cities I’ve been to where it feels easier to walk … but in terms of cycling, and the special relation between cycling and cars, it seems like there’s still friction.”
