When it opened in 1940, the Pennsylvania Turnpike’s Allegheny Tunnel in Somerset County was considered an engineering wonder. Folks marveled at the sheer act of blasting a mile-long hole through a mountain — in this case, the Allegheny Ridge. The two-lane tunnel (one of seven that together totaled 6.7 miles in length) flattened the roadway for motorists and helped usher in the era of the American superhighway.

The westbound tube of the Allegheny Tunnel opened during the launch of the Pennsylvania Turnpike nearly six decades ago. That single tunnel accepted two-way traffic for more than 25 years. The eastbound (southern) tube opened in 1965 to relieve congestion at the four-lane-to-two-lane bottleneck. At the same time, the original tube received a complete overhaul.

Today, the Allegheny Tunnel continues to serve thousands of customers each day, millions each year. But its main systems — from lighting and ventilation to the ceiling slabs and ceramic tiles lining the tunnel walls — need attention. Many of those components are becoming obsolete, and annual operating and maintenance costs for the 1.1-mile tunnel (the longest on the Turnpike’s "mainline") are nearing $2.4 million as a result.

The Turnpike is reassessing the tunnel’s viability and practicality. A team of engineers, environmentalists, archaeologists and tunnel experts has been conducting a detailed analysis of seven tunnel alternatives, taking into consideration factors such as safety, cost and environmental impact. Three of the alternatives propose constructing entirely new tunnels, while three others opt to build a new highway over the mountain. The seventh "No-Build" alternative would restore the existing tunnel.

After two years of careful consideration, the study team recently selected as its preferred alternative the "Brown-Cut," which involves constructing a new, 2.8 mile bypass over the Allegheny Ridge about 610 feet north of the Allegheny Tunnel. With a price tag of $91 million, the Brown Cut is the least costly of the six new-construction alternatives; the other five range in cost from $140-$220 million, with new-tunnel alternatives proving most costly.

But cost is not the only factor that motivated the team to choose the Brown Cut as the preferred alternative.

"The Brown Cut is the option that best satisfies the project needs," said Project Engineer Neil T. Raup, P.E. "We believe it incorporates the optimal balance of cost, environmental impact, engineering criteria and traffic management."

The Brown Cut, which eliminates sharp curves on the east side of the tunnel, involves carving a 220-foot deep notch in the Allegheny Ridge and constructing two river bridges: a 250-foot and a 1,700-foot span. It would relieve bottlenecks at the existing tunnel, and could decrease the accident rate.

The cut would also allow a third truck-climbing lane — which now terminates just prior to the tunnel’s eastern portal — to continue over the mountain’s summit in accordance with the Turnpike’s strict design standards.

And it accomplishes all this without a significant increase in elevation.

State and federal environmental agencies, including the Department of Environmental Protection, the EPA and the Corps of Engineers now must review the Brown Cut alternative. Approval may come as soon as early 2000. After that, the project enters the final design stage, which takes about two years. Then, the two- to three-year construction phase would commence.

"If everything goes as planned, we could see an Allegheny Tunnel bypass on the Pennsylvania Turnpike as early as 2004 or 2005," Raup estimated.

The bypass would be the third such project in the 60-year history of the Pennsylvania Turnpike. The 3-mile Laurel Hill Tunnel bypass was opened in 1964; a second 13.5-mile project that bypassed both the Ray’s Hill and Sideling Hill Tunnels was opened in 1968.

Dramatic traffic-volume increases (156 million vehicles traveled the Turnpike in 1998) have pushed capacity to the limit in the tunnels, which were designed years ago to carry far fewer vehicles.

This roadway improvement project is just a part of the Turnpike’s continuing effort to create the smoothest, straightest roadway for its customers and to uphold its status as one of the safest highways in the nation.

Turnpike leaders are confident that, by eliminating the tunnel altogether, the modern-day traffic woes will decline on that stretch of the highway in Somerset County.

The Pennsylvania Turnpike's Allegheny Tunnel is located 14 miles east of Somerset Interchange #10 and Bedford Interchange #11.