Interstate 78 in Pennsylvania - History

History

Although built to modern-day Interstate Highway standards east of Pennsylvania Route 100, I-78 between PA Rt. 100 and the Berks-Lebanon county line was built mainly to 1960s standards, has characteristic soft shoulders in most locations, and, despite its rural location, a 55 mph (89 km/h) speed limit that is heavily enforced by the Pennsylvania State Police. 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 was a proposed spur from Interstate 78, at which time was the Lehigh Valley Thruway, from 1962 to 1971. The plans were cancelled because the Liberty Bell Shrine was in the path of the proposed expressway, and NIMBYs protested the destruction of Sixth and Seventh Streets. The planned northern terminus would have been between the 15th Street and PA 145 interchanges.

Never built, Interstate 178 was planned to connect U.S. Route 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 was the designation for a spur route that would extend from 78 into Bethlehem. At the time, 78 was designated as the Lehigh Valley Thruway, concurrent with 22, and the route numbering made sense. Unlike I-178, the route was built. When 78 was later redirected south of this area, 378 had no direct connection to 78 and therefore was downgraded to state route status. The route still remains, as a freeway too with exits and their own numbers, which is quite rare for a state route.

When Interstate 178 and 378 were planned (and 378 was built), 78 ran the length of the Lehigh Valley Thruway, and a bypass south of the Thruway, which would be signed as I-278 was thought of. Instead, 78 was rerouted onto this path, after opposition to continue its concurrency with the Thruway into New Jersey.

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.