Why time should not be the only factor in future planning of cities

The 15-minute city, a concept in which essential services are accessible within 15 minutes on foot or by bike, has become increasingly popular in urban planning in recent years. Indeed, it offers solutions to several pressing problems in urban areas, such as traffic, pollution, social isolation and quality of life. With more than half of the world’s population now living in cities (and that number is growing), these issues are becoming increasingly crucial.

In a recent study, published in Cities-NatureResearchers now provide a global quantification of how close cities are to the 15-minute city ideal.

This research team, led by Vittorio Loreto, external faculty member of the Complexity Science Hub, professor at Sapienza University of Rome and director and head of the Sustainable Cities research line at Sony Computer Science Laboratories-Rome (Sony CSL-Rome), then adopted this metric to assess the state of many cities around the world and provided an open-access platform (whatif.sonycsl.it/15mincity) for anyone to explore cities or parts of them.

A global perspective on city accessibility

Using this new measure, the team evaluated and compared cities around the world. “Our results revealed strong disparities in access to services, both within cities and between different regions, meaning that urban areas have a high level of inequality,” Loreto explains. For example, areas with many services in a city may be more expensive and only people who can afford them can live there.

“Globally, many European cities score well on accessibility, with Vienna being a prime example. However, most cities in the US, Africa and parts of Asia have significantly longer wait times to access basic services,” says Loreto.

The research team didn’t just identify these disparities, but went further: What would happen if the same resources and services were redistributed? Would it be possible to increase accessibility, leading to less inequality in a city? Or would it require more resources? In short: does a neighborhood, for example, need a massive improvement in transportation to reach essential services or a more capillary distribution of essential local services?

The relocation algorithm

The researchers attempted to answer these questions by creating a “relocation algorithm,” which will help understand how to increase the number of citizens who can access services in a given urban area and reduce inequality. In addition, the algorithm is also essential for simulating how a city would respond to an increase in services until it reaches the 15-minute frame and how the number of services needed may vary across cities.

“We see considerable differences between cities in the minimum number of additional services needed to meet the concept of a 15-minute city. What is even more interesting is that we see that the very notion of a proximity city is not even conceivable in many cases, and that a radically new paradigm needs to be designed,” explains Loreto.

Beyond time: towards value-based urban planning

Why does this matter? Fundamentally, it helps us better understand the cities we live in, the complex challenges people face, and the various potential solutions. It also shows that no two cities are the same, meaning each requires unique approaches tailored to its complexities. The 15-Minute City is just one of many frameworks that can help address these challenges.

The researchers concluded that the ideal of a city based solely on time is not enough to create a livable city. Instead, we must start creating cities based on values, where local population densities and socio-economic and cultural factors are taken into account.

By using such a model, urban planners, engineers, and policy makers can focus on creating customized solutions for their cities rather than one-size-fits-all approaches. This helps make cities more accessible to a wider range of people. Building more equitable cities has many benefits.

Better access to healthcare, education, culture, amenities and the many opportunities that cities offer as hubs of human creativity help make us more engaged and informed global citizens.