Going with the flow

As reported in the Guardian Online on 09 September 2004

Science can be used to design cities according to rational laws, writes Philip Ball.

‘It was built to be a modern, efficient, healthy and, all in all, pleasant place to live. Many Britons find this amusing.” That’s how Terry Pratchett and Neil Gaiman, in their book Good Omens, describe Milton Keynes, a town for which neither heaven nor hell is prepared to take credit.

But even with one of the highest densities of roundabouts in the country, not to mention the notorious concrete cows, there are far worse places to live than Milton Keynes. The ridicule it suffers is more a reflection of our instinctive scepticism about the idea of rationally designing a city.

Ever since the 19th century, urban design has had an uneasy relationship with science. Amid the grimy horrors of the Industrial Revolution, cities became viewed as inherently undesirable.

“Town planning began as an attempt not to understand cities but to replace them with something better,” says Bill Hillier, director of the Space Syntax Laboratory at University College London. Idealists like Robert Owen aimed to create a bucolic-industrial utopia, and paved the way for “balanced urban environments” such as garden cities.

These visions didn’t really have any theory. They sounded nicer than the bleak, regimented industrial cities that American social theorist Lewis Mum ford dubbed Coketown in the 1930s, but were they truly more conducive to healthy living? What made the problem particularly hard was that no one was quite sure what urban design was. To some, it was architecture writ large, which meant it should embrace the modernism of Le Corbusier. To others, it was a form of social planning that should be rooted in economics.

But the science-based work of Hillier, and his spinoff company Space Syntax, takes a different point of view. If we are going to design good cities, says Hillier, we need first to observe them scientifically to deduce their fundamental rules. He believes good urban planning means relinquishing some control. Cities are organic: they grow, evolve and adapt. “I wouldn’t design a new city,” Hillier says. “I’d grow one.”

This perspective goes back to Mumford, who called the growth of a great city amoeboid. He thought the uncontrolled sprawl of big US cities alienating and disempowering. His protege Jane Jacobs argued that we should trust to the self-organising vitality of cities rather than received ideas of what they should look like.

In her book The Death and Life of Great American Cities, Jacobs attacked urban renewal schemes as a “mad spree of deceptions and vandalism and waste”. Her ideas gave rise to the movement known as New Urbanism, which argues that good cities emphasise characteristics such as walkability, diversity, neighbourhood structure and sustainability. Hillier says his work is an attempt to put Jacobs’ ideas into scientific form.

Some basic ideas of this organic approach to urban design, such as self-organisation and emergence, are now familiar from the area of science dubbed complexity theory. This month, the Prince’s Foundation for the Built Environment will bring together architects and designers influenced by complexity, such as Charles Jencks, alongside theorists like Hillier and scientists working on complexity in biology and physics. This is not bandwagon-boarding; Hillier has spent more than 20 years looking for emergent laws in the interactions between space, objects and human movement.

“Space is a lawful thing,” he says. The basic propositions seem obvious: for example, if you place an object in an open space, then the more centrally it is placed, the more it interferes with movement and visibility. By using these first principles, one can understand how different arrangements of buildings shape patterns of movement and social function.

Cities, says Hillier, have two main functions. In business areas, space is shaped to encourage movement and encounters between people, generating activity and trade. And there are residential areas, where movement and activity is more controlled.

Comparisons between many different cities and cultures seem to point to a universal spatial pattern which Hillier calls “deformed wheel”: a centre linked by radial “spokes” to a surrounding grid of residential areas. This pattern, which can be discerned from Tokyo to Venice to Baltimore, repeats at different scales: in local districts as well as in the whole city.

By encouraging free flow of pedestrians and traffic, the spokes promote safety, in contrast to the preference of some planners to “put us all in cul-de-sacs”. Hillier says that superimposed on this universal structure are culture-specific variations: the complex residential districts of Arabic cities, for example, reflect a stronger separation of public and private life.

Space Syntax, headed by Hillier’s former student Tim Stonor, used these ideas to plan the reconstruction of Trafalgar Square, previously an island surrounded by traffic in which tourists (but not locals) milled about while trying to avoid pigeon droppings. “‘Suits’ used to walk around the edge,” says Stonor. “Now, 13 times more Londoners use the square.”

Space Syntax developed the design by combining on-the-street observations of patterns of pedestrian movement with computer modelling that assumed people’s movements are controlled primarily by their lines of sight. The company also worked on the redevelopment of King’s Cross, and is drawing up schemes to turn Elephant and Castle roundabout into “the Trafalgar Square of south London.”

Space syntax won’t tell us how to make a “perfect” city, but can help to avoid bad ones. While using science as a tool for social planning has often been regarded a potential weapon of totalitarianism, Hillier stresses that in architecture and urban design it is merely a handmaid of art. He compares the “rules” of space with those of language.

“The laws of language do not tell us what to say, but prescribe the structure and the limits of the sayable.” Architecture is, he believes, not a battleground but a meeting place. “It is not half art and half science, but fully art and fully science.”

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