The Pennsylvania Turnpike was opened in 1940; it was the first modern superhighway, and the predecessor to today's Interstate Highway System. Winding its way across Pennsylvania's mountains, it first stretched from the Pittsburgh suburbs to Harrisburg, and with several extensions over the years, now carries vehicles across the entire state.
The Turnpike is sometimes called the "Tunnel Highway." When it opened, seven tunnels carried cars and trucks under some of the taller mountains. Each of these tunnels only carried two lanes of traffic- at each tunnel approach, drivers in each direction were forced to merge into a single lane to pass through. By the 1950s, this had created horrible bottlenecks with massive traffic jams, and something needed to be done.
The Pennsylvania Turnpike Commission found that the simplest approach was to "twin" most of the tunnels, by boring a second tube parallel to the first, creating one tunnel for each direction of traffic. The Allegheny Mountain, Tuscarora Mountain, Blue Mountain, and Kitattinny Mountain tunnels received such treatment. The Commission determined, though, that it would be more cost-effective to bypass the three remaining tunnels- Laurel Hill, Rays Hill, and Sideling Hill- with completely new sections of highway.
The Laurel Hill Tunnel was bypassed in one segment, and the Rays Hill and Sideling Hill tunnels, only a few miles apart from each other, were bypassed together in a longer section. In 1968, all three tunnels were closed down for good as traffic began to travel on the newer highway sections.
All three tunnels have sat vacant for decades. In the 1990s, a Nascar team purchased the rights to use the Laurel Hill tunnel for race car testing. The property is strictly off limits, all trespassing laws enforced. Details of the nature of tests done inside the tunnel have not been made public. The Rays Hill and Sideling Hill tunnels and the 13-mile stretch of abandoned highway they occupy, however, have been left alone. Part of the film The Road was shot here- the abandoned highway and tunnels were a perfect setting, and Pennsylvania's bleak winters make for a convincing post-apocalyptic scene. Nowadays, the road has been unofficially opened as a bike/hiking trail, though it's not maintained and not patrolled, so anyone entering does so at their own risk.
On the day we visited, the weather was absolutely wonderful, much nicer than November usually provides in southwestern PA. With temperatures approaching 60 and the sun shining, we started to hike the abandoned highway. While I was quick to take off my jacket and roll off my sleeves after a few thousand feet of walking, I was glad I had warm clothes as we entered the tunnels- it was cold enough inside to see my breath.
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6. Entrance to the Rays Hill tunnel.

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8. Coming out on the other side...

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11. Approaching the Sideling Hill tunnel.

A scene from The Road was shot here...

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13. Huge ventilation blowers above the tunnel.

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