Interstate 78 in Pennsylvania

Route description

I-78 starts in Pennsylvania at an interchange with Interstate 81. It merges with U.S. Route 22 in Lebanon County, with the median strip becoming narrow at that point; the two run together for 43 miles (69 km) from Bethel Township to Kuhnsville. Near Kuhnsville, U.S. Route 22 splits off from I-78 and becomes the Lehigh Valley Thruway. Near Hamburg at mile marker 29, it meets a major Pennsylvania route: Pennsylvania Route 61. At mile marker 53, after the departure of US 22, Pennsylvania Route 309 merges with I-78 for 7 miles (11 km). Dorney Park & Wildwater Kingdom is visible from the freeway approaching exit 54 for U.S. Route 222, which leads to the park. In Summit Lawn, State Route 309 leaves the freeway toward Quakertown at exit 60. Past Allentown and Bethlehem, Pennsylvania Route 33 meets I-78 at exit 71. The last exit in Pennsylvania is Exit 75/Morgan Hill Road, which connects to Pennsylvania Route 611. The Interstate crosses the Delaware River on the Interstate 78 Toll Bridge, leaving Pennsylvania for New Jersey. Tolls are only required on the westbound side, coming into Pennsylvania.

Names

Interstate 78 carries some additional name designations throughout Pennsylvania. In Lebanon County, Interstate 78 is known as the 78th Division Highway. In Berks County between mile marker 23 and mile marker 35, Interstate 78 is known as the CMSgt. Richard L. Etchberger Memorial Highway, in honor of Richard Etchberger. In Lehigh and Northampton counties, Interstate 78 is known as the Walter J. Dealtrey Memorial Highway. The portion concurrent with US Route 22 shares its designation of the William Penn Highway.

History

Construction of the freeway between Lebanon and Lehigh counties took place between 1950 and 1970, originally as an upgraded alignment of US 22. The entire I-78 route was completed by 1989. When the Interstate Highway System numbers were first assigned in 1957, the route was planned as I-80N. Prior to the late 1960s, I-78 was to be routed on the Lehigh Valley Thruway across to Phillipsburg, New Jersey, continuing the concurrency with US Route 22; however, because of heavy opposition by residents of Phillipsburg, PennDOT and NJDOT opted to build the new southerly alignment on which I-78 is routed today.

Interstate 178

Interstate 178 was a proposed spur from Interstate 78, but was cancelled because the Liberty Bell Shrine was in the path of the proposed expressway. Additionally, locals opposed the destruction of Sixth and Seventh Streets to accommodate the highway. The planned northern terminus would have been between the 15th Street and PA 145 interchanges. If built, Interstate 178 would have connected US 22, formerly designated I-78 into Allentown.

This route was shown in Rand McNally atlases in the late 1960s, but was not included in the 1971 federal interstate route log. The route was supposed to end near Muhlenberg College.

Interstate 378

Interstate 378 was the designation for a spur route that would extend from Interstate 78 into Bethlehem. At the time, I-78 was designated as the Lehigh Valley Thruway, concurrent with US 22, and the route numbering made sense. Unlike I-178, the route was built. When I-78 was later redirected south of this area, I-378 had no direct connection to I-78 and therefore was downgraded to state route status. The route still remains, as a freeway with exits and their own numbers. That is quite rare for a state route.

When Interstate 178 and 378 were planned (and 378 was built), I-78 ran the length of the Lehigh Valley Thruway. Later, I-78 was rerouted onto a bypass route south of the Thruway. This was due to opposition to continue the concurrency with the Thruway into New Jersey.

Improving I-78

In 2013, PennDOT announced plans to improve a portion of I-78 in eastern Berks County. The project will redesign the PA 737 interchange, add truck lanes, and raise the height of three overpasses. Construction is expected to begin in 2015 with completion in 2018.