The 15-minute city

On June 28, 2020, Anne Hidalgo, the first ever woman to hold the office was re-elected as mayor of Paris, re-affirming her mandate to reallocate city space away from cars and towards pedestrians and cyclists. Hidalgo’s goal of making Paris the first, mostly car-free city by the end of her second term is closely related to her support for a vision for urban development termed the 15-minute city.

Developed by Professor Carlos Moreno at the Sorbonne in Paris, the 15-minute idea or “la ville du quart d’heure” is based on research into how people actually use their time when living in major cities and aims to use this insight to improve living conditions and the environment by altering how cities are structured and zoned. For Moreno, the basic needs of city dwellers - work, home, shops, entertainment and healthcare should all be accessible within 15 minutes by foot or by bike.

Core to Moreno’s vision is the aim to cut down unnecessary journeys : “We need to reduce the presence of cars on the streets” he says. As well as being director of entrepreneurship and innovation at the Sorbonne, Moreno is also special envoy to Anne Hidalgo and has been a key advocate of her endeavours to encourage cycle use and to take a broader view of urban development. The mayor had already banned traffic along parts of the Seine and on some Sundays along the Champs-Élysées.

The Covid induced global lock-down has focussed discussion still further with many cities widening cycling lanes in a bid to reduce reliance on public transport. In Paris, Hidalgo has re-purposed red de Rivoli, the often traffic clogged artery that runs from the Marais to the Place de la Concorde to become calm conduit for pedestrians and cyclists.

Legacy and latency

The utopian vision of the 15-minute city and its benefits to the environment and living conditions are part of a global dialogue around the idea of ‘living locally’. In 2018 the Victorian Government in Australia launched the Plan Melbourne 2017-2050. Plan Melbourne is supported by the principle of 20-minute neighbourhoods, in effect the same idea as Paris’ 15-minute city although it is not clear if the saving of an additional 5 minutes is a piece of French one-upmanship or simply better syntax. Similar ideas have also surfaced in Ottawa and Detroit. 

The historical structure of many of our cities can be traced to previous efforts to improve the lives of citizens and the environments they lived in. In an effort to separate housing from the toxic and polluting factories and tanneries of the 1800s city leaders deliberately designated separate areas for living and working. As industry moved out of city centres and work migrated to clean office based environments, the need for this forced separation disappeared and mixed use developments found favour. 

The legacy of this process entwines with the surprising reality that competing companies perform better when they are physically located close to competitors. From the tech hub of silicon valley to the car companies of southern Germany, groups of competitors build mutually supportive networks and suppliers, build talent pools of skilled and experienced workers and gain the critical mass required to influence local politics and developments. At macro level we see this in the ‘Silicon Roundabout’ at Old Street, the design hub of Clerkenwell and traditional centre for diamond trading at Hatton Garden.

The resulting ebb and flow of our cities, the changes in pace and feel from one area to another has created inequalities in the distribution of wealth and the availability of services. The natural desire to live and work in the better areas exasperates the imbalance to the extent that people can no-longer afford to live in the better neighbourhoods and instead commute from cheaper areas. 

In this context the central tenant of the 15-minute city, the even distribution and access to all of the amenities we need in our daily lives is clearly a radical and significant change. By engineering out, at city-wide scale, the need for mass commuting the 15-minute concept resonates with millions who have stopped commuting and successfully worked from home during the pandemic. 

Such an egalitarian vision of communities living and working in carefully organised micro-systems while wasting less time commuting will be hugely appealing to many. But there are inevitable challenges and real concerns with the fundamentals of such an approach.

In Paris there is a long history of authorities actively configuring the fabric of the city. From Haussmann’s master planning of the city for Napoléon to Mitterrand’s Grande Projets the political will and public purse has informed the character and landscape of the entire city. But for the widespread adoption ‘living locally’ most cities will be looking to private investment to drive developments. New York’s Hudson Yards sets out to be the ultimate mixed use development but as it sits largely closed and empty due to the pandemic it is too early to see what has and what has not worked in this $25 billion development.

As well as asking how, we also need to ask if we should look to adopt something akin to the 15-minute plan. By levelling out access to amenities there is a risk of homogenising areas, if every area has everything, where is the different, the special? As the global population is increasingly urbanised where do we go to improve and optimise the model?

The not so ‘smart city’

In 1961 and with no formal training as a planner the urbanist and activist Jane Jacobs published The Death and Life of Great American Cities, introducing then ground-braking ideas about how cities function, evolve and fail. Jacobs saw cities as integrated systems that operated to their own logic and changed over time in relation to their use. A long term resident of Greenwich Village, Jacobs’ writing has influenced a generation of architects, planners and academics including Moreno and his vision of the 15-minute city. 

The inherent complexity of cities and how they work, explored by Jacobs in her writing also influenced a generation of tech savvy architects who looked to apply the ideas and technologies of the digital age to the ancient problems around how best to configure and manage large urban areas. The resulting Smart City movement extolled the digital connection of services, resources and people to better manage the city in real time as a connected whole. 

By blanketing the city with sensors the Smart City is able to react to how it is being used, not over generations or decades as Jacobs observed but constantly, in real time. From monitoring traffic to ease congestion, to analysing sewage to track public health, the real-time city functions as a single organism able to adapt and optimise itself constantly.

This dream of using big data in the build environment has had patchy success. In South Korea the 1,500 acre Songdo development seemed the ultimate master-planned utopia. Residents can remotely adjust the temperature of their apartments via apps while concealed pneumatic tubes send waste from their homes straight to underground waste facility, where it’s sorted, recycled or burned for energy generation. But while the tech works, the social experiment has not. Residents say they feel disconnected, the area lacks the local human interactions that form communities and make them successful. 

Professor Moreno has distanced himself from the ‘smart’ city movement, preferring instead to talk of the ‘living’ city. While acknowledging the importance of the tools that technology brings, he opposes what he sees as the copy-and-paste model being adopted by many proponents of the movement and instead seeks ways to allow communities to co-create solutions.

The best of all worlds

On the 26th floor of a building in the aforementioned Hudson Yards development in New York, a blended team of technologists and urbanists is setting out not just to re-imagine the city of the future but to create the systems and platforms required to facilitate such innovation. Lead by Daniel L. Doctoroff, New York’s former deputy mayor for economic development and rebuilding, Sidewalk Labs is funded by Google’s parent company Alphabet.

Sidewalk Lab’s growing list of products and technologies share the goal of developing digital and physical innovations to improve life in cities. Their Promo-Model X is a model to help facilitate the design and development of high rise timber buildings. Physically lighter and with significant environmental improvements over traditional steel or concrete structures, these ‘mass timber’ buildings combine refreshing aesthetics with improved design and construction processes.

Though good for the environment and interesting architecturally, it is not the development of large timber buildings that offer the most to improve the model for 15-minute cities. It is another of Sidewalk’s innovations that opens pandora’s box.

Generative design is the combination of machine learning with computational design. Simply put, instead of using computers as tools to help draw, the tool is given a data set and and a brief of what is required. The software then creates designs from scratch, often many variations and is able to objectively measure and demonstrate how well they answer the requirements of the brief. 

In their example they show the planning of an inner city neighbourhood. Briefed to create a solution that optimally balances the needs for open spaces, daylight and building density, the system then generates layouts of buildings and open spaces that perform best against those three criteria. Thousands of permutations are created and objectively measured with 400 of them out-performing a baseline proposal created using traditional methods. 

Where the 15-minute plan scores is in the emotive proposition of freeing us from the daily commute in traffic clogged cities. But where it struggles is in reacting to the more nuanced needs of people to enjoy different experiences in different spaces and to be surprised and delighted as they explore and discover.

The time is nearing when a brief of sufficient clarity and complexity can be answered by a generative design tool of sufficient power and sophistication to create a true utopia. Such systems will truly grant communities real involvement in the design of their environment and will shape our cities to better reflect how we really use them.

Or, as the architect Lord Rogers once said of Mitterrand’s Grande Projets, such tools may one day help create “a better place, for modern, democratic man”.