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National Synthesis of Practices Involving "Reasonable Assurance" in Section 106 Compliance and NEPA Decision Making


Highway projects often impact historic buildings and archeological sites, that when funded with Federal-aid funds, triggers Section 106 of the National Historic Preservation Act (NHPA). But those projects develop within a broader context of environmental review required by the National Environmental Policy Act (NEPA). FHWA’s considers NEPA as part of their mission and policies, to balance the need for transportation infrastructure with the costs of eliminating or minimizing a project’s adverse effects to the environment in making decisions in the best overall public interest. And that the NEPA process be one that all environmental investigations, reviews, and consultations be coordinated as a single NEPA process. FHWA further views that NEPA is a decision making process where project decisions be based on preliminary project designs whose final designs must not occur until the NEPA process is complete. In that way, the considerations of the NEPA and umbrella of other environmental impact reviews (i.e., resulting in avoidance, minimization, and mitigation commitments) may be incorporated into a project’s final design. But, this approach has become, for many projects, a source of tension where the time and logistical challenges (i.e., access to private land) delays the completion of NEPA reviews. To address this tension, FHWA policy allows in cases where full compliance is not possible at the time final NEPA documentation is prepared, that NEPA can be completed so long as there is a provision of reasonable assurance that all requirements will be met.

With the signing of Executive Order 13807 there is now a Federal goal of completing major infrastructure projects within 2 years. That policy includes a performance accountability system that tracks each major infrastructure project where Federal agencies must follow a transparent and coordinated processes that must include early and open coordination among Federal, State, tribal, and local agencies and

early engagement with the public. But the dual tensions of making timely decisions and employing NEPA outcomes to infrastructure in an environmentally sensitive manner mean it is more likely that full compliance is not possible at the time the final NEPA documentation is prepared.

These tensions are apparent for Section 106 of the NHPA that requires Federal agencies to consider the impact of their actions on historic properties and provide the Advisory Council on Historic Preservation with an opportunity to comment on projects before implementation. Similar to the considerations of project effects to wetlands or threatened and endangered species and their habitats, the combination of relying on preliminary project design, early agency coordination, and accountability tracking for streamlined schedules, Section 106 requires information on the presence and evaluation of all properties that may be impacted by a project, including ones in locations where access for survey has not been granted. FHWA allows for deferral of full Section 106 compliance only if there is “reasonable assurance” that the Section 106 requirements would be met. “Reasonable assurance” in this case means that the project decision makers have sufficient information about the presence of historic properties and project effects to those properties to complete the NEPA process, (that is the basis for developing a highway infrastructure project), even though the Section 106 process has not completed.

However, in some instances deferring Section 106 identification and consideration of historic properties until after the NEPA decision likely has inhibited appropriate consideration of highway construction effects on historic properties. A project’s NEPA approval marks the point where a project’s location and concept have been decided upon and may proceed to final design and construction with Federal-aid funding. The reason why this consideration is inhibited is because Section 106 allows for the phased identification and consideration of historic properties through program alternatives (i.e., project specific programmatic agreements) that serve to defer the complete identification and consideration of historic properties until after a project’s location and concept have already been established. If sufficient information about the presence of historic properties and project effects to those properties are not adequate at the time of NEPA approval, then their consideration is not part of decision making on a project’s location and concept. This has the outcome of “treating” (or “resolving” in Section 106 parlance) the project effects to historic properties rather than “considering” those effects in deciding a project’s location and concept. Also, deferring full compliance appears to lessen the ability for environmental commitments to become part of a project’s final design. This lessening or diminishing the timely incorporation of environmental commitments into a project’s design because of deferral of full compliance is the problem which is at the focus of this research. More specifically, can the concept of “reasonable assurance” still provide the full detail and variety of information that results from “full compliance?” This proposal has the consideration of historic properties as its focus, but other resources (wetlands, threatened and endangered species) are equally subject to this same problem.


This research, carried out in the form of a national synthesis of practices subject to the reasonable assurance standard, will gather relevant information from subject matter experts to better define both the variety of information and its level of detail necessary to meet the reasonable assurance standard. Because the requirements for the consideration of natural resources and project impacts to those resources are often deferred by applying the same “reasonable assurance standard” this proposal has the potential to inform on the application of this “standard” to a variety of community, cultural, and natural resources.

The following tasks are anticipated to carry out this research:

  • Defining “reasonable assurance” in law, regulation and any relevant case law.

  • Developing 2-Phase Survey Plan

  • Phase I: Brief survey of state DOTs, FHWA Division offices, and State Historic Preservation Officers (SHPO) to determine the level of awareness concerning the reasonable assurance standard and to identify the kinds of Section 106 and other environmental analyses that are typically deferred until after a NEPA decision is made.

  • Phase II: Detailed survey of a smaller number of respondents to more substantially define how the reasonable assurance standard is handled in transportation project development.


State DOTs and their FHWA partners will be able to implement the research results directly into the processes by which Section 106 identification efforts and other environmental analyses subject to NEPA are carried out. A national synthesis of the kinds of Section 106 identification efforts deferred until after a NEPA decision will inform the DOTs and FHWA about successful practices and the kinds of analyses, if any, that are necessary to support a reasonable assurance standard.

Sponsoring Committee:ADC50, Historic and Archeological Preservation in Transportation
Research Period:12 - 24 months
RNS Developer:Owen Lindauer, Antony Opperman
Date Posted:01/09/2020
Date Modified:01/09/2020
Index Terms:
Administration and Management
Planning and Forecasting

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