Welcome to the Preserving the Historic Road International Conference.

We are the leading global forum addressing the identification, preservation and management of historic roads.

US Route 60, Osage Nation (Oklahoma)

Conference History

Preserving the Historic Road International Conference (PTHRIC) began in 1995 as a regional historic roads conference in White Plains, New York, alongside the historic Bronx River Parkway. This initial gathering, focusing on historic parkways in the Northeast, established the need for a larger and national dialogue—how to accomplish such a mission was still unclear.

In 1997 a Cultural Resources Training Initiative grant from the National Park Service and staff support from the National Trust for Historic Preservation and the California Department of Transportation provided the catalyst needed to consider a national conference. The first planning meeting was held at a restaurant on the historic Plaza in Santa Fe, New Mexico during the 1997 National Preservation Conference. The first national gathering to discuss historic roads was planned for the following spring of 1998—Preserving the Historic Road in America, as the conference was first titled, was born.

The mission established for the first conference was to bring together different viewpoints from different perspectives regarding the identification, preservation and management of historic roads in the United States. Founded during a period when many signature historic roads, such as the Bronx River Parkway (New York), were facing imminent threats for destruction and demolition stemming from safety and liability concerns, the conference organized around the idea of bringing engineers and preservationists—often in adversarial relationships—together for frank conversations and information sharing.  Despite the pressures facing many historic roads, this was also a time during which some of the first comprehensive historic road inventories and progressive state transportation policies were being developed—most notably for the Historic Columbia River Highway (Oregon) and the Merritt Parkway (Connecticut).

From the beginning, the conference sought participation in each host state from both the state transportation department and the state historic preservation office.  This unusual partnership—strategic, imaginative and symbolic—earned the conference immediate credibility and was soon mirrored by national-level sponsors from the federal government and advocacy organizations.

Preserving the Historic Road in America created an environment where issues of highway safety and function could be addressed within the context of a historic road facility.  Given the tensions surrounding the topic of historic roads, particularly in the early years, the conference consciously established an environment that would be viewed as objective, neutral and diverse. While the initial purpose behind the conference was halting further losses to the nation’s historic roads, it quickly became a forum for sharing innovations and advancements in technology, research, engineering and historic preservation. After the 2004 conference, the name was changed from Preserving the Historic Road in America to Preserving the Historic Road due to increasing participation by attendees outside the US.  As the conference matured, it became an international forum for historic roads. In 2018, the twentieth anniversary of the conference, the name was changed to Preserving the Historic Road International Conference.

Since the founding, Preserving the Historic Road has striven to create an environment that is enjoyable, collegial, intelligent and purposeful.  As a result, transportation departments have become better stewards of historic roads, and preservationists have become better advocates for flexible design policies that recognize safety and function.  The conference has a proud legacy of education and awareness that has significantly advanced the identification, preservation and management of historic roads in the United States and around the globe.

Past Conferences & Proceedings

Past Conferences


Since the first conference in 1998, academic and professional papers have been collected and assembled as the official proceedings of the conference. The PTHRIC Proceedings represent one of the largest collections of historic roads research in the world.

  • Los Angeles Proceedings, 1998
  • Morristown Proceedings, 2000
  • Omaha Proceedings, 2002
  • Portland Proceedings, 2004
  • Boston Proceedings, 2006
  • Albuquerque Proceedings, 2008
  • Washington, DC Proceedings, 2010
  • Indianapolis Proceedings, 2012
  • Savannah Proceedings, 2014
  • [No conference, 2016]
  • Fort Collins Proceedings, 2018

Arroyo Seco Parkway, c. 1940, Los Angeles, California. Credit: California Department of Transportation