Any serious reduction in American driving will require more than this — it will mean changing how and where many of us live.It ain't never gonna happen. Krugman himself acknowledges that this won't happen until the residential structure shifts to the cities, along with the tranportation infrastructure.
To see what I’m talking about, consider where I am at the moment: in a pleasant, middle-class neighborhood consisting mainly of four- or five-story apartment buildings, with easy access to public transit and plenty of local shopping.
It’s the kind of neighborhood in which people don’t have to drive a lot, but it’s also a kind of neighborhood that barely exists in America, even in big metropolitan areas. Greater Atlanta has roughly the same population as Greater Berlin — but Berlin is a city of trains, buses and bikes, while Atlanta is a city of cars, cars and cars.
And in the face of rising oil prices, which have left many Americans stranded in suburbia — utterly dependent on their cars, yet having a hard time affording gas — it’s starting to look as if Berlin had the better idea.
Changing the geography of American metropolitan areas will be hard. For one thing, houses last a lot longer than cars. Long after today’s S.U.V.’s have become antique collectors’ items, millions of people will still be living in subdivisions built when gas was $1.50 or less a gallon.
Infrastructure is another problem. Public transit, in particular, faces a chicken-and-egg problem: it’s hard to justify transit systems unless there’s sufficient population density, yet it’s hard to persuade people to live in denser neighborhoods unless they come with the advantage of transit access.
By that time, the energy crisis will be over.
The world is swimming in energy. We don't have an energy crisis. We have an energy portability crisis first and foremost, and we have a greenhouse gas crisis secondarily. Both of these problems arise because fossil fuels have a larger energy density than any alternative.
That's a technology problem, one that's being worked on agressively. There will be solution. The portability issue gets solved with batteries or fuel cells. The carbon issue gets solved with nukes (fission or fusion), PV, solar thermal, wind, or some combination therof. But in thirty years--the earliest conceivable timeframe for an infrastructure refresh of the kind Krugman envisions--the problem is either solved or so obviously on the way to being solved that nobody's going to trade in their nice quiet suburb for the nearest city.