Pittsburgh, PA – Pennsylvania Department of Transportation (PennDOT) Secretary Mike Carroll was joined today by regional and transportation-industry leaders for a dedication ceremony to recognize the Liberty Tunnels Ventilation System as an American Society of Civil Engineers (ASCE) National Historic Civil Engineering Landmark in the City of Pittsburgh, Allegheny County.
Today’s ceremony was held to unveil the newly installed plaque at the Liberty Tunnels Fan House dedicating it as an ASCE National Historic Civil Engineering Landmark (NHCEL). The NHCEL program recognizes historically significant national and international civil engineering projects, structures, and sites. The Smithfield Street Bridge is the only other ASCE NHCEL in the City of Pittsburgh and the only other existing NHCEL in Allegheny County.
“I am excited to be part of acknowledging this historic landmark site today,” said Carroll. “The department has come a long way from the early ventilation systems, and I thank the ASCE Pittsburgh Chapter for recognizing this system’s advanced engineering nationally. Our tunnel maintainers are an around-the-clock operation, and they routinely monitor these systems to ensure public safety.”
The Liberty Tunnels – comprised of two parallel but separate tunnels with four lanes in total – opened to automobile traffic in January 1924. This was America’s first automobile-only tunnel with this specific design. At over a mile in length, it was the longest auto tunnel upon opening.
The need for new kinds of public safety systems – including cross-passages and a ventilation system – for such a long tunnel were recognized from the start of the design. As little was known about human health impacts of gases discharged by motor vehicles in tunnels, a significant research and development effort was initiated to support the design of a ventilation system that would protect the public. The tunnel design engineers, led by civil engineer Almos D. Neeld (an 1875 civil engineering graduate of the University of Pittsburgh), engaged and collaborated with the U.S. Bureau of Mines research lab, which was in Pittsburgh. The collaborative research and design effort developed knowledge and methods that advanced tunnel ventilation engineering nationally.
"The ASCE Pittsburgh Section pursued the historic landmark designation as a way to recognize the 100-year anniversary of the Liberty Tunnels and their importance to the Pittsburgh region,” President of the ASCE Pittsburgh Section Taylor DaCanal said. “The ventilation system for the Liberty Tunnels was the first such system for an automobile tunnel in the U.S. and influenced the designs of the Holland Tunnel in New York, the Sumner Tunnel in Boston, and others."
PennDOT’s Bridgeville-based District 11 maintains four tunnels in the City of Pittsburgh and Stowe Township. It takes 76 employees to conduct around-the-clock operations with 226,000 vehicles on average using these tunnels daily. Tunnel maintainers respond to approximately 2,000 incidents a year and work in conjunction with other emergency personnel in Allegheny County.
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MEDIA CONTACT: Nicole Haney, nhaney@pa.gov or 412-429-5011
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