The right kind of sprawl

EVERY year the world’s urban population swells by about 75m people. That extraordinary growth—equivalent to adding eight Londons—is a wonderful thing. Cities throw people together, encouraging the exchange of ideas. The people who move there tend to grow richer, freer and more tolerant. What is rather less wonderful is the way in which many of the world’s fastest-growing cities are expanding.

The trouble is not, as is often claimed, that cities in poor and middle-income countries are spreading like oil slicks. Most of them need to expand. Western cities can often accommodate their growing populations by squeezing more people in. But many poor cities are incredibly dense already: Dhaka, the capital of Bangladesh, is nine times as tightly packed as Paris, if you include their suburbs. And no Western city has ever added inhabitants as quickly as the poor and emerging-world champions are doing. African and Asian metropolises are bound to sprawl even if sensible pro-density reforms are passed, such as scrapping height restrictions on buildings.

The real problem is that these metropolises are spreading in the wrong way. Frequently, small housing developments or even individual houses are plonked down wherever a builder can cut a deal with a farmer (see article). In the huge, jumbled districts that result, far too little space is set aside for roads. Manhattan is 36% road (overall, almost half of that capitalist temple is public space). In some unplanned African suburbs as little as 5% of the land is road. Even middle-class districts often lack sewers and mains water. As for amenities like public parks, forget it.

Suburbs can eventually be retrofitted with roads and sewers. But that will be horrifically complicated and expensive—too much so for poor countries. It would be vastly cheaper and better to do sprawl properly from the start.

Urban and national officials should begin by admitting two things: their cities are going to become very much larger; and this growth will be too quick to be controlled by comprehensive urban plans. Officials in poor countries often spend many years drawing up detailed plans; by the time they are finished, the city has changed so much that their designs cannot possibly be implemented.

It is wiser to keep things simple. At a minimum, work out where the main thoroughfares and parks will go as the city expands. Again, New York is a good model. In 1811, when the city was still confined to the southern tip of Manhattan, it planned for a sevenfold expansion and laid out a street grid.

Make way

Acquiring rights of way for future roads and amenities can be both costly and politically difficult (though not nearly as much as waiting until it is too late). Almost all fast-growing cities are in countries where landholdings are small, and small farmers do not take kindly to being booted off their land. But a few countries have developed a promising technique known as land readjustment. Instead of evicting farmers in the path of a new road, officials offer to reorganise a whole district. Everybody loses some land, and the biggest winners—those closest to the new road—compensate those who fare less well. Japanese cities used this technique when they were growing quickly. Today the Indian state of Gujarat makes it work.

Increasingly, the world’s fastest-growing cities will be African. And those are especially hard to corral. Many African countries persist with some form of collective land ownership, which is anathema to professional developers: why buy land that you cannot formally own? Until farmers are given full rights to their lands, including the ability to transfer legal title, cities are likely to grow in a messy way. Good planning and secure property rights make for a better kind of sprawl.