Preservation, Rehabilitation, Restoration, Reconstruction
While the term “historic preservation” is widely accepted to entail all the actions and activities surrounding the recognition, care and prevention of the loss of the buildings, structures, districts, landscapes and roads of the past, “preservation” also has a more specific definition associated with the nature of work and maintenance at a historic site. In fact, preservation, restoration, rehabilitation and reconstruction, terms that tend to get used interchangeably, have very specific meanings and implications for historic resources. When undertaking a plan of action for a historic road, it is important to select the appropriate terminology for the activities being planned or promoted. It is very likely that a plan for a historic road will engage two or more of the activities defined by United States Secretary of the Interior’s Standards for the Treatment of Historic Properties. These standards refer to how a property will be used, altered, maintained and protected.
preservation: Preservation applies to properties that are largely intact and reflect the period(s) of significance. This would refer to historic roads and road resources that maintain their original design and materials in good condition. Under preservation, activities and actions associated with such resources largely focus on maintenance and care.
The careful replacement of bricks or cobblestones dislodged by frost-heave or utility work, use of non-chemical de-icing agents to prevent damage to a limestone bridge abutment, the removal of weeds in the gutter on a bridge deck, regular resurfacing of an asphalt highway or annual inspection of street trees by an arborist are examples of preservation of the existing resources.
rehabilitation: Rehabilitation applies to properties that are largely intact and reflect the period(s) of significance, but may require some repair or alteration. This would refer to historic roads and road resources that maintain their original design and materials in fair condition, or roads and resources requiring modification for safety. Under rehabilitation, activities and actions associated with the resource are focused on maintenance, care and sensitive replacement or modification on a limited basis.
The introduction of a visually unobtrusive box beam rail along a segment of a historic road that historically had no barrier, but requires one today, would be an example of rehabilitation. Similarly, the replacement of a historic wooden barrier with a new wooden barrier with steel reinforcing on the back would also be an example of rehabilitation.
restoration: Restoration applies to properties that retain significant components of the period(s) of significance, but may require some repair or alteration, or the removal of features/additions not identified as contributing features. Under restoration, activities and actions associated with the resource are focused on maintenance and care of intact historic features, replacement of lost features and removal of inappropriate features.
The removal of a Jersey barrier erected in front of a Beaux Arts bridge balustrade would be an example of restoration. The removal of added traffic lanes or a shoulder added after the period of significance would also be an example of restoration.
reconstruction: Reconstruction applies to properties that are largely beyond repair or have been lost. Under reconstruction, the design, appearance and materials of the original road or road features are recreated. For an historic road, this may include the complete replacement of a concrete pavement that has degraded beyond repair, utilizing the original specifications and construction techniques.
The complete removal and replacement of a failed (or failing) concrete pavement with a new road surface, built to the standards used for the original road construction, would be an example of reconstruction. Similarly, rebuilding an early toll house that was demolished would be an example of reconstruction.
Period of Significance
A well-established period (or periods) of significance is as important for historic roads as any other historic resource. They should be distinctive and cohesive periods with a strong historic context. A period of significance associated with a particular historic road will share a common history, technology and details. For roads with extended histories there may be multiple periods of significance. Periods of significance may be very short—five days for Dr. Martin Luther King’s civil rights march along the Selma to Montgomery Highway in Alabama—or last over a period of decades—1926 to 1960 representing the heyday of auto travel and culture on U.S. Route 66. The period of significance determined for the National Register application for the Bronx River Parkway in Westchester County is 1915-1930.
For aesthetic and engineered routes there is almost always an initial period of significance associated with the years of design, construction and initial use. Cultural routes are more likely to have multiple periods of significance as changes in transportation or use affected the evolution of the historic road. The National Road in Pennsylvania, for example, has identified four primary periods of significance—Early Trails and Military Roads (1750-1810), Construction of the National Road (1806-1834), Toll Road Era (1830-1900) and The Automobile Era (1890s to present). Each of these periods represents a particularly intensive time of activity, use and change. Across the border in Maryland, three periods of significance have been identified for the National Road. For each state, fortifications, taverns, toll houses and gas stations are among the architectural artifacts from these eras. Maryland and Pennsylvania demonstrate that there is considerable latitude in the development of a period(s) of significance for historic roads. When considering period of significance questions, establish or identify the significant dates or eras for which the historic road was new, innovative or in transition. It is, of course, possible from the analysis that a period of significance associated with the historic road, while well documented, has no remaining artifacts that can tell the story of the historic road today.
 This period of significance is generally cited by Route 66 scholars. A National Park Service study, Special Resource Study: Route 66, identified 1926 to 1970 as the period of significance for Route 66. It is often impossible to assign exact dates for periods of significance. The 1960 date, often cited, applies more to the popular culture of Route 66, while the 1970 Park Service date is a more technical reference looking broadly at Route 66 resources.
 The State of Maryland identifies three periods of significance for its stretch of the National Road: Heyday of the National Road (1810-1850), Agriculture and Trade (1850-1910) and Revival of the National Road (1910-1960).