Nobody expects Americans to give up their cars, but we may never again drive the way we once did, and Pittsburghers could be ahead of this trend.

Though we have not slammed our feet on our brakes as dramatically as other large metro areas, we never drove as much in the first place. In a sense, America is decelerating toward us.

These are among the findings in a Brookings Institution report released this week, "The Road ... Less Traveled."

An accompanying news release proclaims "a permanent shift away from reliance on the car," but that's a bit of an overstatement. It's more accurate to say we're shifting to a lower gear. The Brookings study is thick with numbers, and here are a couple:

• American vehicles traveled 90 billion fewer miles in the 12-month period ending in September, compared with the year before. (That works out to more than 3.6 million trips around the world Americans didn't take, if my math is right.)

• Among the 100 largest metro areas in the United States, only a dozen drive fewer miles per capita than Pittsburgh. We averaged 4,604 miles per man, woman and child, just a little more than half the rate of America's most drive-happy metro area, Jackson, Miss. We can safely say all the sprawling outward, all the hollowing inward, that metropolitan Pittsburgh has done over the past few decades still leaves the bones of a strong way to get around.

Robert Puentes, co-author of the Brookings analysis, has no doubt that the areas that drive least will fare best in the years ahead. The little break we're getting lately with $2 gasoline is a side effect of global recession and isn't going to last.

I reached Mr. Puentes on his cell phone in Washington as he was preparing to take a K Street bus across town. He says he's "not anti-car by any stretch of the imagination," but he hopes to provide texture to the national conversations on what to do about the Detroit Three and rebuilding America's infrastructure.

One point everyone should be noticing, he says, is "almost complete saturation in household vehicle ownership."

That might mean that November's car sales, the lowest in 26 years, are a portent rather than a blip. Sales of vehicles in the United States sunk to a seasonally adjusted annual rate of 10.18 million, from 16.07 million the year before. I believe that the car industry that crawls from this wreckage will need a business model that can be profitable at that lower number, or close to it.

Following that thought, we need to rebuild highways and bridges, but there isn't much need to add capacity for traffic that may never arrive. The question of the stimulus plan should not just be whether projects are "ready to go" but whether they are based on growth and driving patterns that remain realistic.

"Do we really need highways to nowhere?" Mr. Puentes asks.

When I asked about the Mon-Fayette Expressway, that billion-dollar-plus toll road that ends well south of Pittsburgh, he called it "a great example of a roadway project we may need to rethink."

We are about to enter a transportation funding crisis because highway funding is dependent on state and federal gasoline taxes. The rates haven't risen in years and, with people driving less and buying less gasoline, there aren't as many tax dollars coming in. The federal highway trust fund is expected to fall $8 billion to $9 billion short, Mr. Puentes said.

Do we fill that gap from the general fund, adding billions to the debt we're heaping on our children? Or do we take advantage of this temporary decrease in gasoline prices and raise the gasoline tax, thereby curbing demand and paying for some of these projects as we go?

Nobody likes a tax increase, but this tax money could be plowed back into highway and transit projects that would prepare America for the inevitable oil price increases that will arrive when worldwide demand returns.

"We could capture some of that [gasoline price] increase and keep it here instead of outsourcing it," Mr. Puentes said.

Some final points: The two metro areas with the fewest vehicle miles per capita are the New York-Northern New Jersey-Long Island area and Lancaster, Pa. The former has subways and commuter railroads, while the latter has the Amish. Each offers its own lessons in efficiency and/or thrift.

Closer to home, the fifth-most drive-happy metropolis in the country is Harrisburg-Carlisle, Pa. You don't suppose all those state vehicles we buy are being overused, do you?