Since its opening 50 years ago, I-81 has changed Pa.

Associated Press

In the half-century since the first section of Interstate 81 opened in Pennsylvania, the northeast-southwest highway has transformed the landscape, bringing economic growth and new opportunities but also new problem.

The highway, which enters northeast Pennsylvania and then slices toward the center of the commonwealth before exiting in south-central Pennsylvania, is one leg of the multibillion-dollar 1950s-era effort to unite the country with a grid of superhighways from coast to coast and border to border.

And “the nation’s grandest infrastructure project” has delivered on its promise, according to a Central Pennsylvania Joint Reporting Project series this week by the (Chambersburg) Public Opinion, The (Carlisle) Sentinel, and the Lebanon Daily News with the aid of Shippensburg University journalism students.

For central Pennsylvania, the transportation link has brought diversified economies and even international headquarters to county seats such as Chambersburg and Carlisle. A former rural crossroads, Lickdale near Fort Indiantown Gap now boasts restaurant and motel chains, warehouses and plans for an industrial park.

“I-81 has stimulated economic growth,” said Jack Benhart, retired chairman of the Shippensburg University geography and earth science department. “It’s opened the area to commercial, industrial and residential development. If we just had Route 11, the area may not have been developed, or it might have been at a much slower pace and in a much different environment.”

Construction of what was announced as the “Cumberland Valley Freeway- Anthracite Expressway-Penn Can Highway” link between Hagerstown, Md., and Binghamton, N.Y., began in Pennsylvania in 1958 and took 17 years to complete. Most local work was completed in the 1960s, with the first section opening in 1961.

The highway has become a truckers’ route, and a 2004 Pennsylvania Department of Transportation study predicts that truck traffic in 2030 will approach the current total traffic.

The populations and incomes of the four counties bordering I-81 in the area have grown faster than the state average, and pockets of urbanization can pop up at any exit. But that has also meant a free ride for traffic, air pollution, drugs and crime.

And Pennsylvania, like other states, has been trying to keep up with the aging interstate system. The commonwealth has spent more than $60 million in recent years to repair bridges on and spanning I-81 in Franklin and Cumberland counties. A proposal to widen the highway to six lanes has been shelved.

In addition, when the lines were drawn, designers merely connected the population centers, giving little thought to the consequences of paving over open farm country with rich soil.

In fact, many people didn’t believe growth was coming at all. Behart, who moved to the Shippensburg area in the late 1960s, said his father-in-law counted four cars on I-81 on the trip from there to Carlisle and wondered whether the highway was needed. Today, he would likely count more than 1,000 vehicles on the half-hour trip, and more than 40,000 a day travel that section of I-81, according to PennDOT’s most recent traffic count in 2008.