Back in 1961, the gradual decline of many city centres in the U.S. began to puzzle urban planners and activists alike. One of them, the urban sociologist Jane Jacobs, began a widespread and detailed investigation of the causes and published her conclusions in , a controversial book that proposed four conditions that are essential for vibrant city life.
Jacobs’s conclusions have become hugely influential. Her ideas have had a significant impact on the development of many modern cities such as Toronto and New York City’s Greenwich Village. However, her ideas have also attracted criticism because of the lack of empirical evidence to back them up, a problem that is widespread in urban planning.
Today, that looks set to change thanks to the work of Marco De Nadai at the University of Trento and a few pals, who have developed a way to gather urban data that they use to test Jacobs’s conditions and how they relate to the vitality of city life. The new approach heralds a new age of city planning in which planners have an objective way of assessing city life and working out how it can be improved.
In her book, Jacobs argues that vibrant activity can only flourish in cities when the physical environment is diverse. This diversity, she says, requires four conditions. The first is that city districts must serve more than two functions so that they attract people with different purposes at different times of the day and night. Second, city blocks must be small with dense intersections that give pedestrians many opportunities to interact.
The third condition is that buildings must be diverse in terms of age and form to support a mix of low-rent and high-rent tenants. By contrast, an area with exclusively new buildings can only attract businesses and tenants wealthy enough to support the cost of new building. Finally, a district must have a sufficient density of people and buildings.
While Jacobs’s arguments are persuasive, her critics say there is little evidence to show that these factors are linked with vibrant city life. That changed last year when urban scientists in Seoul, South Korea, published the result of a 10-year study of pedestrian activity in the city at unprecedented resolution. This work successfully tested Jacobs’s ideas for the first time.
However, the data was gathered largely through pedestrian surveys, a process that is time-consuming, costly, and generally impractical for use in most modern cities.
De Nadai and co have come up with a much cheaper and quicker alternative using a new generation of city databases and the way people use social media and mobile phones. The new databases include OpenStreetMap, the collaborative mapping tool; census data, which records populations and building use; land use data, which uses satellite images to classify land use according to various categories; Foursquare data, which records geographic details about personal activity; and mobile-phone records showing the number and frequency of calls in an area.
De Nadai and co gathered this data for six cities in Italy—Rome, Naples, Florence, Bologna, Milan, and Palermo.
Their analysis is straightforward. The team used mobile-phone activity as a measure of urban vitality and land-use records, census data, and Foursquare activity as a measure of urban diversity. Their goal was to see how vitality and diversity are correlated in the cities they studied.
The results make for interesting reading. De Nadai and co say that land use is correlated with vitality. In cities such as Rome, mixed land use is common. However, Milan is divided into areas by function—industrial, residential, commercial, and so on. “Consequently, in Milan, vitality is experienced only in the mixed districts,” they say.
The structure of city districts is important, too. European cities tend not to have the super-sized city blocks found in American cities. But the density of intersections varies greatly, and this turns out to be important. “Vibrant urban areas are those with dense streets, which, in fact, slow down cars and make it easier for pedestrian to cross,” say the team.
Jacobs also highlighted the importance of having a mixture of old and new buildings to promote vitality. However, De Nadai and co say this is less of an issue in Italian cities, where ancient buildings are common and have been actively preserved for centuries. Consequently, the goal of producing mixed areas is harder to achieve. “In the Italian context, mixing buildings of different eras is not as important as (or, rather, as possible as) it is in the American context,” they say.
Nevertheless, the team found that a crucial factor for vibrancy is the presence of “third places,” locations that are not homes (first places) or places of employment (second places). Third places are bars, restaurants, places of worship, shopping malls, parks, and so on—places where people go to gather and socialize.
The density of people also turns out to be important, too, just as Jacobs predicted. “Our results suggest that Jacobs’s four conditions for maintaining a vital urban life hold for Italian cities,” conclude De Nadai and co.
They go on to summarize by saying: “Active Italian districts have dense concentrations of office workers, third places at walking distance, small streets, and historical buildings.”
That’s an interesting study that has the potential to have major impact on city planning. The lack of an evidence-based approach to city planning has resulted in numerous urban disasters, not least of which was the decline of city centers in the U.S. in the 1950s, 1960s, and later.
This new era of city science could change that and help create vibrant, vital living spaces for millions of people around the world.
Ref: arxiv.org/abs/1603.04012 : The Death and Life of Great Italian Cities: A Mobile Phone Data Perspective
While the intended purpose of the article “Data Mining Reveals the Four Urban Conditions That Create Vibrant City Life” in the MIT Technology Review (14 March 2016) was to illustrate how big data and data mining can be used to validate (or disprove) claims originally derived from purely observational research and / or a limited sample, I was rather more intrigued by the conditions that create vibrant city life. I thought it would be interesting to contemplate whether it might be possible to ‘translate’ these condition into contexts of other communities, such as networks, or organisations.
The article introduces conclusions from observational research conducted by urban sociologist Jane Jacobs in the early 1960s that have become rather influential for town planning, yet there had always been some unease as there was not enough ‘evidence’ to prove that these observations were correct. Here the four ingredients she had identified as critical for creating vibrant cities:
- Districts should have a variety of functions so they attract people at different times of the day, ie there should be residential buildings, offices, industrial facilities, entertainment places, education facilities, recreation facilities, museums, libraries, and galleries.
- Individual blocks should be small and offer intersections where people can interact rather than large and rectangular blocks, which create long distances and often only have one particular use.
- Conditions of buildings should vary so they attract different economic income groups.
- Districts should have sufficient density of both people and buildings.
In a paper recently presented 14th March 2016 at the 26th International ACM Conference on World Wide Web (WWW), De Nadai of the University of Trento and his colleagues have used a number of datasets to test these four conditions in the cities of Rome, Naples, Florence, Bologna, Milan and Palermo.
To measure urban density they used data sets from the following sources:
- The collaborative mapping tool OpenStreetMap,
- Census data, which records populations and building use;
- Land use data, which uses satellite images to classify land use according to various categories;
- Foursquare data, which records geographic details about personal activity;
To measure vitality they used mobile-phone activity (number and frequency of calls in an area).
Fundamentally, whether based on observations in the 1960s or datasets from the second decade of the 2nd millennium, the conditions that create vibrant cities remain the same. Two additional insights. First, the age and condition of buildings was found to be less important – which the researchers attributed to the fact that the building stock in the cities under review was overall quite old. Second, they found that ‘third places’ are a crucial factor for vibrancy. To clarify, homes are ‘first places’, places of employment are ‘second places’, ‘third places’ are bars, restaurants, places of worship, shopping malls, parks, etc, where people can meet and be.
Looking at organisations you are familiar with, what are your observations?
- Is the physical environment monotonous and repetitive, with corridors and floors that all look the same? Or is there a variety of different spaces and styles?
- Are corridors and floor spaces endless with no spaces to stop and talk? Or is an effort being made to create diverse, smaller spaces that have their own character and invite to connect and converse?
- Is the physical environment in organisations broken down by functions – be the separation by floor or even buildings? Does the segregation continue to rest areas and even parking spaces? Or is it easy for people from different departments and levels to bump into each other?
- Has down- and right-sizing lead to empty spaces? Or is there a nice buzz to the organisation?
Looking at the last point in particular, it seems to me that we are not looking at linear relationships but rather a u-shaped one. Surely, we do not want an empty space – nor an overcrowded one!We don’t want a uniform environment – nor do we want our sense to be overwhelmed by too much variety. A vibrant community lives at the magic place of complexity where we are neither numbed by monotony, nor overwhelmed by chaos.
To read the MIT post please click here.
PS I found the lovely picture googling for ‘vibrant space’ on the website of the American Society for Landscape Architects.