After two decades, a plan to replace the Pennsylvania Turnpike’s longest tunnels is back on the table. The Turnpike Commission is considering six options for abandoning the parallel 6,070ft (1.8km) long Allegheny tunnels in Somerset County. Three involve constructing new tunnels and three include open-cut highway routes through the mountain either to the north or south of the existing tunnels.
The first Allegheny Tunnel, which carries westbound traffic, was built in the late 1930s and the second opened in 1965. On the Northeast Extension, the second tube of the Lehigh Tunnel opened in 1991 after 34 months of tunneling. It is 4,380ft (1,335m) long.
Preliminary cost estimates for the Allegheny Tunnel “open cut” options range from $242 million to $345 million, while estimates for the tunnel options range from $537 million to $694 million.
Turnpike spokesman Carl DeFebo said the cost differential was just one of several factors the commission will consider in choosing a preferred option, possibly in the spring. After that, design, acquiring property and securing permits would take four years and construction at least two years