Every weekday morning, Arlington County, Va., wakes up to a grinding form of musical chairs.
Some 70 percent of its resident workforce leaves the county to work somewhere else. Meanwhile, an even bigger phalanx of nonresidents come in to the county to do their jobs. The excess congestion, pollution, and lost productivity makes smart-growth advocates say: Isn't there a better way to handle sprawl than to swap suburban populations during the day?
Arlington can't be written off as a fluke. Gilpin County, just outside Denver, sends out nearly as great a share of workers as Arlington and gets a bigger share back. West Baton Rouge Parish in Louisiana sends out 60 percent of its workers and imports 60 percent more to do its work.
In all, 17 counties from Florida to Massachusetts to Colorado export and import at least half their workforce on a typical weekday. And scores more counties are moving toward that dubious distinction, according to new census figures released this week.
Even though jobs are following Americans out of the cities and into the suburbs, it seems the exoduses still don't line up. Indeed, jobs and workers often end up far apart. That's a major factor behind the three-minute increase in the nation's average commute during the 1990s. And it explains why a growing share of Americans are crossing county lines to reach their jobs.
"We certainly see a huge increase in travel time," says Phillip Salopek, a demographer in the population division of the US Census Bureau in Suitland, Md. "Jobs move out to the suburbs, and employees move to exurbs."
The new data suggest that in the vast majority of counties - rural as well as urban - an increasing share of employees is crossing county lines to get to work. Nationally, 23 percent of Americans worked outside their county of residence in 2000 - up from 20 percent in 1990 and 18 percent in 1980.
While much of this rise comes from workers' desire to live in less congested places, other factors also play a role.
Take housing prices. Some residential markets have gotten so pricey workers can't afford to live near their work. San Francisco County, Calif. - one of the nation's most expensive housing markets - imports nearly half its workforce.
Geography also plays a role. Because counties are smaller in the East, workers are more likely to cross them than workers in the West. Thus, the census county data underestimate the amount of commuting in the West.
Workers' skills and needs can also affect commuting. Arlington County, the home of the Pentagon, attracts highly skilled workers who may choose to live in more exclusive areas. At the same time, its housing may prove too costly for the people who staff the county's low-end service jobs, suggests Alan Pisarski, an independent travel-behavior consultant in Falls Church, Va., and author of "Commuting in America."
He adds that since three-quarters of workers live in households with another worker, locating near one person's job may mean a long commute for another.
Interestingly, the growth in rural commuting seems just as strong as metro-area travel. For example, seven of the 17 musical-chair counties don't fall within a metropolitan area. And in five of those, most of the jobs for which workers are commuting aren't located in metro areas either. Rural work accounted for all but 66 of the jobs for residents of Calhoun County, Ark.
One of the puzzles facing researchers is why the commutes keep getting longer. After all, the factors behind the big rise in commuting during the '70s and '80s have nearly played themselves out, Mr. Pisarski argues. Baby boomers and women have already entered the workforce. The automobile's dominance as the transportation of choice means little room for new gains from public transportation or carpooling.
Changes in the way the Census Bureau measures commuting probably account for one of the average three extra minutes. Even so, a two-minute jump would represent three times the 0.7-minute increase of the 1980s.
One possible factor: immigration.
"Immigrants are moving very quickly from public transportation to cars," says Robert Lang, director of the Metropolitan Institute at Virginia Tech in Alexandria, Va. And they're also moving rapidly to the suburbs.
If that's happening, though, it's taking place somewhere other than the 17 musical-chair counties. All but one is primarily white (Greensville County, Va., is primarily black). And while Hispanics represent sizable minorities in a couple of the 17, the overwhelming majority of musical-chair residents are US born.
"Immigration is the great wild card," Pisarski says. "I'm seeing the impact of immigration on almost everything."