Lloyd has looked at the correlation between urban density and driving habits before, but has also concluded that medium density cities are often more sustainable than the uber-dense. This debate seems to be heating up again, with George Monbiot arguing for strict planning laws, compact cities, and high density, while David Boyle over at the New Economics Foundation suggesting Monbiot has it all wrong, and medium density is the way to go:
First, the evidence about energy use and densities is not nearly as clear cut as he suggests. Very low densities like Los Angeles mean high energy use, but so do very high densities like New York and Tokyo. The spectrum between those makes very little difference.
Second, future cities are going to have to provide for their own needs, growing water and using waste as raw materials for new industries. Both those activities require space. High density living means trucking the food in every morning and the waste out every night. It is old economic thinking.
Third, the human spirit requires nature. Our mental health requires access to trees and growing things. High density cities are a recipe for insanity for the poor. That's not sustainable either.