Abandoned Pennsylvania Turnpike

The Abandoned Pennsylvania Turnpike is the common name of a 13-mile (21 km) stretch of the Pennsylvania Turnpike that was bypassed in 1968 when a modern stretch opened to ease traffic congestion in the tunnels. In this case, the Sideling Hill Tunnel and Rays Hill Tunnel were bypassed, as was one of the Turnpike's travel plazas. The bypass is located just east of the heavily congested Breezewood interchange for Interstate 70 (I-70) eastbound at what is now I-76 exit 161.

When the Pennsylvania Turnpike opened in 1940, it was known as the "Tunnel Highway" because it traversed seven tunnels: from east to west, Blue Mountain, Kittatinny Mountain, Tuscarora Mountain, Sideling Hill, Rays Hill, Allegheny Mountain, and Laurel Hill. There was one tunnel through each mountain, and the highway was reduced to a single lane in each direction through each tunnel. These tunnels were originally built as part of the South Pennsylvania Railroad. One short tunnel was bypassed during the original construction of the Turnpike.

By the late 1950s, the turnpike was so heavily used that traffic congestion demanded expansion. The Pennsylvania Turnpike Commission (PTC) conducted studies on either expanding or bypassing the tunnels. The result was the "twinning" of four tunnels (by constructing a second, parallel, two-lane tunnel), and outright bypass and closure of the other three. The tunnels through the Blue, Kittatinny, Tuscarora, and Allegheny mountains were expanded through the "twinning" process, while the other three were bypassed. The Laurel Hill Tunnel, located on the border of Westmoreland and Somerset counties, was one of these tunnels, though the bypass was only around two miles (3.2 km) long.

...
Wikipedia