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The Road To The Future

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Authors: Dan Cupper

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May/June 1990 | Volume 41, Issue 4

Most American motorists take for granted the concrete and asphalt web of interstate highways that has penetrated so deeply into the nation’s economy and thinking. The 43,000-mile system of fouror-more-lane divided, limited-access roads reaches from the canyons of California to the beaches of Florida and the urban bustle of the Northeast Corridor. But of course there was a time when the superhighway idea was brand-new. In the United States, it all began with the Pennsylvania Turnpike—a road that, fifty years ago this October, profoundly changed the way Americans perceived time and distance. Not only was the Pennsylvania Turnpike the nation’s first major toll road, it was also, more significantly, our first long-distance, highspeed, limited-access, four-lane divided road —the direct conceptual predecessor of the interstate system. It was built with four 12-footwide lanes and wide, safe shoulders; long, level straightaways and gentle curves; and grades of no more than 3 percent (a three-foot rise for every hundred feet of forward travel). Even more striking was its seamless, gradeseparated design: no cross streets, traffic lights, business entrances, railroad crossings, trolley cars, or pedestrian access. All local and state roads were realigned to pass over or under the turnpike, and the only commercial concessions allowed on the highway were ten gas-station-and-restaurant plazas with their own entrance and exit ramps. Most remarkable, the highway did all this while running virtually at right angles to the ridges of the rugged 2,900-foot-high Allegheny Mountains. By using six uncompleted tunnels left over from an abandoned nineteenth-century railroad project and one new tunnel, the turnpike kept its climb to a minimum.

The original section extended for 160 miles from Middle-sex, about 15 miles west of the state capital at Harrisburg, to Irwin, about 20 miles east of Pittsburgh. Previously, motorists traveling between these cities had had to contend with one of two narrow two-lane roads: the Lincoln Highway (U.S. Route 30) or the William Penn Highway (U.S. Route 22). Both were built with sharp curves and steep grades (as high as 9 percent) because of the mountainous terrain, which made them hazardous in winter. Long-haul trucking companies so dreaded the mountains that many of them routed East-to-Midwest shipments hundreds of miles out of the way, taking either U.S. Route 6 across northern Pennsylvania or the lakeshore route through Buffalo, New York. When the turnpike opened, it reduced the accumulated climb from 13,000 feet, via Route 30, to less than 4,000 feet. It also cut 5 to 18 miles off the distance of a trip between Pittsburgh and Harrisburg, and the length of time for such a trip, dropped from six hours in good weather to less than three. Many motorists covered the 160 miles in two and a half hours.

Pennsylvania’s statewide speed limit at the time was 50 miles an hour, but with trucks sharing the mountainous two-lane roads, motorists were lucky to average much more than half of that. (Of the 3,000,000 miles of highway in the United States in