No matter how big the city is, your commuting distance won’t change

Carlo Ratti is an Italian architect, engineer, inventor, and educator. He has many impressive titles, including being named one of the “Names You Need to Know” by Forbes, one of the “25 People Who Will Change Architecture and Design” by Blueprint magazine, one of the “50 Most Influential Designers in America” by Fast Company, one of the “50 People Who Will Change the World” by Wired magazine, and one of the “60 Inventors Shaping Our Creative Future” by Thames & Hudson.

As the head of the MIT Senseable City Lab, Ratti and his team have conducted many valuable and forward-thinking studies on “cities” and have provided many pioneering proposals for urban development. For example, they developed an autonomous ferry that can transport people across a river and proposed the idea that “dispersion is transportation, and aggregation is a floating bridge.” They also conducted research on shared transportation in Manhattan before the concept of “ride-sharing” became commercialized and proposed solutions for it.

imgWhen I first visited their official website, my initial reaction was: can I understand any of this?

Urban issues always give people a grand feeling, and their focus on exploring cities with advanced technology seems to elevate this topic to a more difficult-to-understand dimension.

But don’t be too quick to give up. At the end of the day, a city is just a place where we live, and it’s not that complicated. Today, we plan to introduce Carlo Ratti and his lab in a different way and share some of the “cool facts” they have discovered about cities.

Fun Fact 1: Commuting Distance Doesn’t Change Regardless of City Size

This is a project they completed last year, with an interesting name (which I don’t quite understand why it’s named this way) called the “Potato Project”. It’s a study of the “commuting distance pattern in cities” based on a sample of 234 cities in China.

They collected and organized mobile phone location data from over 50 million residents in more than 200 cities, including Beijing, Shanghai, Hangzhou, Guangzhou, and Harbin. Finally, they came up with two significant commuting patterns in cities.


Firstly, the commuting distance at the city level is not related to the city’s size. This is somewhat counterintuitive because we tend to think that the larger the city, the longer the commuting distance. However, their research shows that regardless of the city’s size, the average commuting distance is quite similar, at about 5 miles (approximately 8 kilometers).

For example, Shanghai and Daqing have a tenfold difference in population, but their average commuting distances are very similar, with Shanghai at 8.82 kilometers and Daqing at 8.64 kilometers.

Of course, considering that larger cities may have more severe traffic congestion problems, the commuting time in larger cities may exceed that of smaller cities.

In addition, they also derived an “attraction law,” which means that there is an upper limit to the employment attraction of the city center to residents. When the city develops to a certain size, and the commuting distance of residents to the city center increases to a certain extent, the employment attraction of the central area will weaken, and those who live farther away will turn to “sub-centers” to find job opportunities.

Among the dozens of cities studied, the upper limit of the “employment attraction” of the city center is between 6 and 9 miles (approximately 9.6-14.5 kilometers), with Shanghai at 7 miles (11.3 kilometers) and Chengdu at 6 miles (9.7 kilometers).

In fact, this study also reveals the law of urban development from the perspective of commuting distance, that is, when the city expands to a certain extent, the original “single center” will turn to a “multi-center” mode. In other words, to some extent, the “commuting limit” forces the city to develop multiple central areas.


Fun Fact 2: Stolen Bikes Don’t Go Far

“We thought those bikes would be sold overseas, but in reality, they never left.” This is how Fabio Duarte, Chief Research Scientist at MIT Senseable City Lab, describes the initial purpose of their research.

Amsterdam is one of the most bike-friendly cities in the world, which also means it’s a “paradise” for bike thieves. Every year, over 850,000 bikes are stolen (the actual number may be even higher). However, being stolen is just the beginning for these bikes. Researchers were curious: where do they all end up?

The conclusion is that most stolen bikes never leave Amsterdam, and in fact, they don’t even leave the city center much.

img Out of 100 bikes placed in the experiment, 70 were stolen, and 50 of them frequently visited the city center. © MIT Senseable City Lab

This is probably not a surprising result. Their research shows that most stolen bikes are quickly resold, which means that many citizens in Amsterdam may be riding stolen bikes.

Although this research may not seem very “practical” or have any particular “height,” and it may not be used to track and combat theft organizations, the research team points out that it provides essential information for Amsterdam’s bike theft problem. Using very simple technology, they captured the “fencing patterns” of stolen bikes.

Currently, this data and information have been shared with municipal institutions to help them solve this problem.

In addition, there is an interesting “positive conclusion,” which is that although so many bikes are stolen every year, they are quickly put back into use, proving that this issue has not had much impact on Amsterdam’s bike traffic (serious face).

Fun Fact 3: Beijing and San Francisco Look the Most Alike

Here’s another seemingly useless but interesting study called “In]distinct Cities.”

It’s actually quite simple: based on over 2 million social media photos, researchers developed a model to extract and quantify the unique landscapes of 18 cities around the world and analyze their visual similarities. The result is a map where you can select any city and see its unique visual identity as well as the city it looks most like.

Map of cities with circles representing their uniqueness and lines representing their similarity to other cities. The line between Beijing and San Francisco is the thickest.The circles on the map represent the uniqueness score of each city, and the thickness of the lines connecting them represents their similarity. As you can see, the line between Beijing and San Francisco is the thickest.
© MIT Senseable City LabImage of Beijing and San Francisco side by side.© MIT Senseable City LabImage of Singapore and Hong Kong side by side.Singapore looks the most like Hong Kong. © MIT Senseable City Lab

In fact, the conclusion is not the most important or only important aspect of this study. It developed a method to analyze and interpret urban landscapes in a more quantitative and visual way, creating an image data-driven framework and using machine learning to understand urban development and formation.

It not only shows us the importance of city streetscapes in representing local characteristics beyond landmarks, but also identifies some unusual natural landscapes as visual elements with local information. Additionally, they found that taxis, police cars, and ambulances are the most location-specific objects in terms of vehicles.

Furthermore, all the photos were taken from social media, which in a way can serve as a research material for social media observation.
The results of this work have inspired many fields and provided valuable references for the achievements of large-scale geotagging data in understanding place formalization and urban design.

A picture of a city

Do you remember Carlo Ratti’s shiny titles mentioned at the beginning of this article? As a “person who will change the world,” his research and the laboratory he leads are not just for providing us with these “cool facts” about cities.

He is very good at using the latest technology to intervene in urban research and design proposals.

As an example, as mentioned at the beginning, even before ride-sharing services were introduced, they studied the “sharing power” of New York City taxis (this project was called “HubCab” and was published in 2014). By collecting and organizing data from hundreds of millions of trips, they provided substantial progress in solving social sharing issues, such as traffic congestion and environmental pollution, while reducing the operating costs of related organizations.

A screenshot of HubCab, showing the pick-up and drop-off locations of 170 million taxi trips in New York City in one year. Yellow represents pick-up locations, and blue represents drop-off locations. © MIT Senseable City Lab

In addition, in 2021, they used 3D scanning technology to conduct a comprehensive morphological measurement analysis of Rocinha, the largest favela in Brazil, capturing the most detailed and ingenious building practices in the area, while also revealing the terrible lack of infrastructure in the area, demonstrating Rocinha’s construction logic with unprecedented accuracy.

This project has brought informal but important urban spaces like favelas into the realm of digital urban research and is a crucial step in smart city research.

From the perspective of a complete outsider, the research of MIT Senseable City Lab may seem difficult to understand, and many aspects may seem too “advanced” or “useless.”

However, this does not prevent their research from being interesting, meaningful, and inspiring.
Their work can be broadly summarized as “smart cities,” using advanced technology to quantitatively and visually study cities and improve urban life through various technological proposals and design solutions. However, I prefer Carlo Ratti’s definition of their work as “sensing cities.”

According to Ratti, the focus of “smart cities” is on technology, while “sensing cities” are more focused on people, their experiences, feelings, past, and future. Looking at their research and projects from this perspective, it is easy to immerse oneself in their vision and thinking, and sense the breath and growth of the city.

At this year’s MINDPARK Creative Conference, Carlo Ratti will be a keynote speaker in the “technology-driven” section, sharing their rich experience and professional knowledge in urban design, technology integration, and solving current and future urban challenges.

Technology is not just technology; it shapes our way of thinking while changing our way of life. Therefore, when facing technology, we should not only consider how to use it, but also how to approach urban issues from different perspectives based on existing and future advanced technologies, and how our designs can be compatible.I believe that Carlo Ratti can bring you a lot of inspiration and enlightenment on this issue.