Recent data suggest that half, if not more, of our nation’s historic spans have been lost in the last 22 years–two decades in which transportation and preservation awareness reached unprecedented levels. This is an alarming and sobering statistic.

Bridge building paced the evolution of building technology but had a much more enduring impact on engineering, manufacturing and the settlement of the U.S. Surviving bridges are tangible evidence of this legacy but we are fast approaching the point of no return in saving some prime examples.

On Aug. 10, 2005, President Bush signed the $286.4-billion transportation bill funding roads, bridges and rail over the next six years. While the Historic Bridge Program remains, the new legislation did not include two proposed rule changes for historic bridges in Title 23, Section 144 (o) that would have allowed more funding.

A classic example of the problem is the 1920 10th Street Bridge, spanning the Missouri River on eight double-ribbed concrete arches in Great Falls, Mont. Long closed to traffic, this National Register-eligible structure was slated for demolition eight years ago after a new crossing was constructed. Fortunately, local residents saved it and the city won a $250,000 Save America’s Treasures grant to help rehabilitate it. The bridge received another $750,000 in funding and a third of it has been rehabilitated.

An additional $2 million is needed. Changing Section 144 (o) would allow cities like Great Falls to compete for other Title 23 funds. Without access to additional funding, the work is stalled.

Though we have a national historic bridge program, it is not working well enough. In 2003, the Federal Highway Administration, American Association of State Highway and Transportation Officials, SRI Foundation, National Trust for Historic Preservation and the National Park Service’s Historic American Engineering Record organized a workshop of experts to examine the issues surrounding historic bridges. The goal was to provide transportation agencies, Congress and the public with recommendations on how to preserve this heritage. The report, published in 2004, can be read at

One strategy suggested was to extend the extremely successful National Historic Covered Bridge Preservation Program to include other historic bridges as a demonstration project. The logic behind this proposal is that all states have historic metal truss bridges while only 29 have covered spans. Though the covered bridge program continues to the tune of $10 million, adding other bridge types would not require additional funding in the context of the overall transportation appropriation.

The workshop also suggested that states develop historic bridge management plans, which could support other actions, such as programmatic agreements, best practices and improved data accessibility. Management plans should be bridge specific, rather than general.

Every attempt should be made to identify bridges where rehabilitation is appropriate and feasible, especially rare ones like cast and wrought iron trusses, bowstring arches and early reinforced concrete spans. This logically follows completion of the statewide historic bridge inventories that Congress mandated 18 years ago.

Historic bridges symbolize fundamental American values of craft, entrepreneurship and creativity. These artifacts of the American landscape are threatened with extinction and selected examples should be saved for posterity.

Eric DeLony is an engineering and industrial heritage consultant who retired two years ago as chief of the National Park Service’s Historic American Engineering Record. He can be reached at or 505-466-1448.