Millions of hectares of cropland in the industrial world have been paved over for roads and parking lots. Each U.S. car, for example, requires on average 0.07 hectares (0.18 acres) of paved land for roads and parking space. For every five cars added to the U.S. fleet, an area the size of a football field is covered with asphalt. More often than not, cropland is paved simply because the flat, well-drained soils that are well suited for farming are also ideal for building roads. Once paved, land is not easily reclaimed. As environmentalist Rupert Cutler once noted, “Asphalt is the land’s last crop.”
The United States, with its 214 million motor vehicles, has paved 6.3 million kilometers (3.9 million miles) of roads, enough to circle the Earth at the equator 157 times. In addition to roads, cars require parking space. Imagine a parking lot for 214 million cars and trucks. If that is too difficult, try visualizing a parking lot for 1,000 cars and then imagine what 214,000 of these would look like.
However we visualize it, the U.S. area devoted to roads and parking lots covers an estimated 16 million hectares (61,000 square miles), an expanse approaching the size of the 21 million hectares that U.S. farmers planted in wheat last year. But this paving of land in industrial countries is slowing as countries approach automobile saturation. In the United States, there are three vehicles for every four people. In Western Europe and Japan, there is typically one for every two people.