Measuring growth by zip code

Twenty-five years ago, the Lansdale exit on the Northeast Extension was a drowsy interchange with four toll booths that opened onto an area of cornfields and factories.

Modernized and expanded, the Lansdale interchange now has 10 toll lanes - some with EZPass - that handle 12 million vehicles a year. And the Lansdale economy has been updated, too, with business services companies, retail strip plazas, corporate centers, and health-care facilities.

"There's a lot of new rooftops up here," Bob Wrigley, president of Trefoil Properties L.P., a commercial and retail developer with offices in the area, said last week. "It seems like there is a drugstore on every corner."

The Lansdale area is part of an outer-suburban belt that produced the most new jobs in the Pennsylvania suburbs since the mid-1990s, according to new data on job growth by zip code from the Metropolitan Philadelphia Indicators Project at Temple University.

This belt stretches from Kennett Square in southern Chester County to Doylestown in central Bucks County.

In South Jersey, Mount Laurel and Marlton had large employment gains, according to the data. The towns are farther-out suburbs, but on, or near, the New Jersey Turnpike.

In Philadelphia, areas around institutions, such as the airport and the University of Pennsylvania, also added thousands of jobs.

Twenty-one city zip codes gained jobs, and 26 lost jobs since the mid-1990s.

Older bedroom suburbs in Bucks and Delaware Counties in Pennsylvania and Camden County in South Jersey trailed the outer-belt suburbs and rejuvenated areas of Philadelphia.

The zip-code data confirm that the job markets in the distant suburbs have boomed, following residential construction in those areas. The information shows a highly fragmented labor market, one that increasingly is "arranging itself along major roadways," said David Elesh, an associate sociology professor at Temple University and a principal investigator on the indicators project.

The underlying information for the zip-code data comes from the U.S. Census Bureau for the years 1995 and 2004. The indicators project at Temple is being partially funded by $2.1 million from the William Penn Foundation, a nonprofit.

Steve Wray, executive director of the Economy League of Greater Philadelphia, said some experts have described the Philadelphia region as having "an exit-ramp economy." New office complexes follow highways, such as Routes 202 and 422 in Chester and Montgomery Counties, he said.