Hands-On History features stories that focus on history in practice at museums and historic sites throughout Pennsylvania.

Pennsylvania could just as easily be called the “land of bridges” as it is the Keystone State. With more than 83,161 miles of rivers and streams, there has always been a need for residents and visitors to cross water by ferry, ford, or bridge. The Commonwealth’s topography, with its mountain ranges and valleys, also require structures facilitating passage. Today, the Keystone State counts more than 31,727 bridges, of which 25,327 are state-owned and 6,400 locally-owned, in addition to privately-owned spans.

Great scrutiny has been paid to the condition of bridges since the horrific collapse, in August 2007, of an interstate highway bridge above the Mississippi River in Minneapolis, Minnesota, which resulted in the loss of thirteen lives, dozens injured, and hundreds of millions of dollars in property damages and business losses. Concern with the safety of the Commonwealth’s bridges prompted the launch of Rebuild Pennsylvania, a program announced by Governor Edward G. Rendell on May 23, 2008, to tackle bridge repairs, flood-control projects, and new rail and aviation projects. The governor cited that the Commonwealth ranks first in the nation in the number of structurally deficient bridges. He urged the Pennsylvania Department of Transportation (PennDOT) to spend $200 million annually for the next ten years to repair 4,600 of the 6,023 structurally deficient state bridges. A structurally deficient bridge, as defined by PennDOT, refers to its lack of structural soundness and its ability to service the traveling public.

While the safety of motorists is a paramount issue, Rebuild Pennsylvania’s Accelerated Bridge Program concentrates on infrastructure and maintenance, including rehabilitation and preservation measures. Pennsylvania needs to also consider the effects of the program on its historic bridges and heritage tourism, both of which are vital to the economy and quality of life. Everyone wants safe highways and bridges-but at what cost to history? The need for safe highways and bridges and the preservation of engineering landmarks and aesthetics must be carefully balanced.

The Keystone State is inordinately rich in the number and types of bridges, many of which were the first of their kind in the United States. Nine bridges have been designated National Historic Civil Engineering Landmarks and hundreds are listed in the National Register of Historic Places. Pittsburgh’s 1883 Smithfield Street Bridge, spanning the Monongahela River, has been designated a National Historic Landmark. Such status, however, does not guarantee their preservation.

In 1996, PennDOT surveyed the Commonwealth’s road bridges. The survey identified nearly twelve thousand bridges more than fifty years old, including Philadelphia’s Frankford Avenue Bridge, in continuous use since 1697, eight spans surviving from the eighteenth century, 499 bridges dating to the nineteenth century, and the balance constructed in the twentieth century. A precise count of the bridges erected more than fifty years ago is currently being calculated.

PennDOT has undertaken 894 bridge projects in the last five years, many of which have involved replacement. Metal truss bridges, in particular, are being replaced quickly and will soon be the rarest type of historic bridge in the Commonwealth. The 1996 bridge survey identified 854 metal truss bridges in Pennsylvania. Since then, 231 of these bridges have been replaced, at a rate of about 23 a year. In the next four years, PennDOT’s Transportation Improvement Program will replace an additional 130 metal truss bridges, an average of about 35 bridges yearly. At this rate of replacement – coupled with the Commonwealth’s goal to correct the problem of structurally deficient bridges – there will be no metal truss bridges extant in twenty years.

Currently there are 197 wooden covered bridges and 365 stone arch bridges in Pennsylvania. Historians believe the metal truss bridge should be at least as well represented throughout the Commonwealth as other types of historically significant bridges. The metal bridge was once the most popular type in the United States, especially in the years following the American Civil War. Metal trusses proved stronger and more fire resistant than wooden spans, and relatively inexpensive and easy to erect. They are critical to understanding America’s engineering heritage and transportation history.

Historic buildings, structures, landscapes, and bridges are not only important to understanding transportation history, but also to heritage tourism as significant attractions for visitors from other states and countries. For many, crossing a covered, a stone arch, or a metal truss bridge is a tangible link to the past and offers a pleasant experience.

Experience has proven that historic bridges can only be saved when someone cares about them. Older bridges of any type are often difficult to preserve, due to the lack of funding available for maintenance and rehabilitation, the perceived tort liability, inadequate weight capacities, or the traveling public’s desire for speed. Highway departments receive federal and state funding earmarked specifically for bridge replacement but little maintenance money, which would extend the use of historic bridges. Many spans deemed historic will never meet the highest standards for safety and speed; however, many can continue to meet motorists’ needs.

Lack of planning, loss of historic resources, and the replacement of historic bridges all contribute to the loss of character and undeniable sense of place that Pennsylvania possesses. Interestingly enough, residents increasingly want traffic-calming projects, reduced speed limits, and retention of narrower roads and bridges to limit the speed and size of vehicles in their communities. When it comes to bridges that serve as picturesque gateways to communities or enhance the rural landscape, many citizens affirm that the aesthetic quality offered by historic bridges is more important than speed.

Preservation issues are best addressed as a local effort. Pennsylvanians need to act before it is too late and there are no metal truss bridges surviving in Pennsylvania. Think about your community or county – are there bridges that are special? They may not be there in the next ten years.


How to Help Save Historic Bridges

  • Learn about bridges scheduled for replacement under the Accelerated Bridge Program by visiting Rebuild Pennsylvania Accelerated Bridge Program website.
  • Contact county commissioners, bridge departments, local historical societies, regional planning offices, tourist promotion agencies, and voice your concern about the loss of historic bridges.
  • Attend public meetings involving the replacement of historic bridges in your area and request that bridge rehabilitation alternatives be studied. If a bridge is slated to be replaced in a historic district, ask that the new bridge is sensitive to the design of surrounding buildings and landscape.
  • Encourage your municipality or local PennDOT district to establish maintenance funds for historic bridges and develop policies and procedures for their preservation.
  • Urge PennDOT to develop and adopt a statewide management plan for metal truss bridges and all historic bridges to ensure they are preserved.
  • Inform legislators of your concerns for historic bridges in their districts, as well as historic spans throughout the Commonwealth.


Susan M. Zacher, a native of western Pennsylvania, has lived in Harrisburg for thirty-two years, since joining PHMC’s Bureau for Historic Preservation in 1976. She received her bachelor’s degree from Clarion University of Pennsylvania and a master’s degree from the Pennsylvania State University. A historic preservation specialist, she has reviewed state and federal projects for the past twenty-five years to identify potential threats to historic resources and served as coordinator of the National Register of Historic Places program in the Commonwealth. She wrote The Covered Bridges of Pennsylvania: A Guide, published by PHMC.