Tuesday, May 28, 2013

The social consequences of urban design and building structure

The social consequences of urban design and building structure

Jane Jacobs’s eyes on the street, and an econometric critique of Le Corbusier’s high-rise public housing

by Rozalia Kepes 

The 20th century challenged the urban environment in many ways: growing industrialism, the proliferation of cars and the migration of the rural masses to cities resulted in such radical social changes that even the rapid technological development could barely keep abreast of them. It is thus not surprising that the modern architects focused much less on ornamentation and diversity, and much more on function, efficiency, and standardized simplicity, which they intended to realize by comprehensive urban planning. Among the most influential of them was the Swiss-French architect Le Corbusier, whose works had a long-lasting effect on European and American urban design.

According to Le Corbusier, the only way to avoid the dirty and over-crowded slums that had emerged as a consequence of the industrial revolution was to construct high-rise, high-density buildings surrounded by parks. He planned to house the growing population of the cities vertically, not horizontally, in order to provide as many people with space and sunlight as possible, and at the same time to give way to the new mechanization: the automobile. As it is visible on the picture below – the Plan Voisin, illustrating Le Corbusier’s 1925 design to reconstruct downtown Paris – , his vision was to set up a set of isolated high-rises, each surrounded by a little island of park, and connected by wide roads occupied by heavy traffic.

Most of Le Corbusier’s critics, such as the members of the “townscape movement”, emphasized the “urban experience”: this meant that instead of the professional architects’ pleasure, what should really matter was the residents’ perception of the city. It was the zealous journalist, Jane Jacobs, who – with her intuitive and lucid writing – explained why Le Corbusier’s well-meaning plan of providing the poor with high-rise public housing was a bad idea. As it is demonstrated by Gerda Wekerle, Jacobs’s “critique of public housing design included a discussion of long, unwatched corridors, unguarded elevators, stairwells and courtyards that become settings for rape, theft and vandalism”.

Jane Jacobs emphasized the importance of “eyes on the street”, which hypothesis became known as one of her most influential contributions to urban sociology and economics. This means that high density areas, instead of being a source of discomfort, are in fact more than desirable: private monitoring, the positive externality coming from the presence of others on the street can play a crucial role in stopping crime. Therefore, Le Corbusier’s high-rise buildings, by increasing the physical distance between the average apartment inhabitant and the street below, reduce crime prevention.

Two world-famous economists, Edward Glaeser and Bruce Sacerdote used econometric methods to test the eyes-on-the-street model. Using the Federal Bureau of Investigation’s Uniform Crime Reports database, they estimated the frequency of per capita crime rates, and found striking results. Their regressions showed that while burglary and petty larceny (theft without threat of violence) were in no way connected with the percentage of population living in tall apartment buildings or in detached houses, street crimes (i.e. robberies and car thefts) occurred significantly more frequently around multi-unit dwellings. To be precise, „the predicted level of victimization is 6.7 percent greater in a big apartment building relative to living in a single family detached house” (once they control for sex, ethnicity, income, education, marital status, age and public housing).

Furthermore, they managed to show that it was not the number of apartments in the house, but the number of floors (therefore the height of the building) that really mattered. These results seem to prove that Jane Jacobs was right – the more people (and thus their eyes) are lifted away from the street-level, the more dangerous the street (but not the apartment itself!) will become. At the same time, this seems to prove Konrad Lorenz wrong, who in his book On Aggression, had argued that it is simply the density of multi-unit dwellings that makes people more aggressive: had he been right, we would have observed more crime of every sort, not only of street crime.

It is my hope that the example of high-rise dwellings has proved how complex effects urban design and building structure can have on social phenomena, and how important economic analysis is in evaluating the potential consequences of a policy decision.

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