Archaeology at PennDOT
Archaeological Investigations

PennDOT's archaeology program adheres to practices and procedures that apply to most large state and federal agencies. Those procedures serve to insure that proposed transportation improvement projects will do no unnecessary harm to the Commonwealth's archaeological heritage, and they guarantee that unavoidable effects to important archaeological sites will be mitigated with state of the art research. Guided by this process, and working with some of the most

talented archaeologists in the Commonwealth, PennDOT's approach to archaeology is innovative, thorough, and has achieved some spectacular results.

By law, archaeological investigations are required whenever a PennDOT project is expected to have an adverse effect on an important archaeological site. As part of the research and planning for these investigations, PennDOT works very closely with other State and Federal agencies, the State Historic Preservation Office, interested parties, and the general public, to identify and evaluate archaeological resources, to determine the effects transportation projects are likely to have, and to develop procedures for avoiding, minimizing, or mitigating any impacts to the buried past.

Whenever possible, PennDOT makes every effort to avoid archaeological resources. Avoidance is always our first choice, since it leaves archaeological sites undisturbed for future generations and is usually the least expensive option as well. If avoidance isn't an option, or if we are uncertain about the locations and significance of archaeological sites in a proposed project area, or the proposed project's potential effects on such sites, then archaeological investigations are conducted. Typically, these are conducted by consulting firms working for the Department, and they occur in a series of three sequential levels or phases of work.

A Phase I , or identification level survey, is intended to identify the locations of potentially significant archaeological resources. This usually involves a systematic examination of some portion of a proposed project right of way or study area. The methods employed vary, but can include checking the Pennsylvania Archaeological Site Survey files, the inspection of freshly plowed fields, the excavation of small shovel test units, the use of remote sensing

technology such as ground penetrating radar, and speaking to knowledgeable local informants. If the Phase I survey indicates the presence of potentially important archaeological sites that might be affected by the project, the Department may try to implement a project design that avoids the site or sites, or it may proceed with the next level of archaeological investigation.

Phase II archaeological investigations target sites for a formal evaluation of their significance. Specifically, Phase II's are designed to produce information that will determine the site's eligibility for listing on the National Register of Historic Places. Typically, Phase II's involve excavating a sample of a specific site in a series of regular squares or rectangles known as

test units. The units may be of various sizes, but one meter and five foot squares are often employed. If an analysis of the data produced by the Phase II indicates the site is not eligible for listing on the National Register, a transportation project can proceed with no effects to the buried past. If the Phase II indicates the site is eligible for the Register, the Department will attempt to design the project to avoid or minimize any adverse effects to the site. If that's not possible, work at the site may proceed into the final phase of archaeological investigation.

Phase III is often referred to as data recovery or mitigation excavation. These are large-scale archaeological samples of important sites, and they're intended to mitigate the adverse effects a transportation project may have on a site that's eligible for or listed on the National Register of Historic Places. They often feature the excavation of substantial numbers of contiguous excavation units,

or excavation blocks, and they employ sophisticated and painstaking methods of research and analysis. These are the Departments most ambitious, and expensive, efforts at archaeological research, and some PennDOT data recoveries have literally rewritten what is known about some aspects of the Commonwealth's past. Watch this website for updates, as we plan to post both technical documents and popular summaries of some of our most important Phase III investigations as downloadable PDF files beginning sometime in mid-2001!