Compliance with Section 106 of NHPA is a critical requirement of Federal transportation projects. This section of the law, as its implementing regulation, 36 CFR 800, notes, “seeks to accommodate historic preservation concerns with the needs of Federal undertakings through consultation among the agency official and other parties with an interest in the effects of the undertaking on historic properties….” (36 CFR 800.1(a))

As can be seen in this quote from the regulation, consultation is at the heart of the Section 106 process. Consultation is a “process of seeking, discussing, and considering the views of other participants, and, where feasible, seeking agreement with them regarding matters arising in the section 106 process” (36 CFR 800.16(f).

In addition to the NHPA, there are other important laws and regulations that address historic preservation issues and federal projects. These include:

• Section 4(f) of the U.S. Department of Transportation Act
• National Environmental Policy Act of 1969 (NEPA)
• Archaeological Resources Protection Act of 1979 (ARPA)
• Native American Graves Protection and Repatriation Act of 1990 (NAGPRA)

Information on the National Environmental Policy Act can be found in the NEPA Process section of this website. Section 4(f) of the U.S. Department of Transportation Act and its relationship with Section 106 is briefly described below. ARPA and NAGPRA, for the most part, apply to actions on federal and Indian tribal lands. Transportation projects located on federal or Indian tribal lands, therefore, must comply with these laws and their implementing regulations. Information on these two latter laws is provided in the ARPA regulation and the NAGPRA regulation.

Section 106 of the National Historic Preservation Act

Section 106 requires federal agencies to take into account the effects of their undertakings on historic properties and afford the Advisory Council on Historic Preservation (ACHP) an opportunity to comment on the effects of the undertaking. The regulation implementing Section 106 of NHPA is 36 CFR 800. The outcome of the Section 106 process, as laid out in the regulation, is not predetermined. Rather, it is the interaction among the participants involved in this consultative process that determines the outcome, although the final decisions are made by the Federal agency.

Undertakings requiring compliance with Section 106 include projects and programs that are funded, permitted, licensed, or authorized by a federal agency, both on and off federal lands. Historic properties are sites, buildings, districts, structures, or objects listed in or eligible for listing in the National Register of Historic Places. The National Register is used as the standard for defining those historic places worthy of preservation and protection. These historic places include archeological sites, bridges and roads, buildings, designed landscapes such as parks, and places of religious and cultural significance to Indian tribes, Native Hawaiian organizations, and other traditional communities.

The Advisory Council on Historic Preservation is an independent federal agency that advises the President and Congress on historic preservation matters, encourages the preservation of historic properties through review of federal agency programs and projects, and promotes the preservation of historic properties by providing training, developing guidance, and assisting the public. The ACHP also has the authority to issue regulations for Section 106 compliance.

Participants in the Section 106 Process

Federal agencies are at the center of the Section 106 process. They have the responsibility under the law and the regulation for ensuring that the Section 106 compliance process is completed. For projects involving multiple Federal agencies, one agency often will serve as the “lead” Federal agency, taking responsibility for Section 106 compliance and consulting with the other agencies as needed. For highway projects, this is generally the Federal Highway Administration (FHWA), with much of the day-to-day work being conducted by transportation agencies. Even though they delegate the day-to-day work to transportation agencies, FHWA has the responsibility for carrying out the Section 106 process and the authority to make all decisions. FHWA can only assign its responsibility and authority to a state following the assumption of responsibility provisions established in Sections 6004 and 6005 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) and the Moving Ahead for Progress in the 21st Century Act (MAP-21). However, the FHWA cannot delegate government-to-government consultation with tribes.

The Advisory Council on Historic Preservation participates in the Section 106 process based on the criteria in Appendix A of 36 CFR 800. The ACHP generally participates in the process when the undertaking will have substantial impacts on important historic properties, will be highly controversial, or will have issues of concern to tribes and Native Hawaiian organizations. In addition, the Federal agency requests the ACHP to participate in the Section 106 consultation process when an undertaking will adversely affect a National Historic Landmark.

The other participants in the Section 106 process are referred to as consulting parties. These include State Historic Preservation Officers (SHPOs), who serve as the state’s representative in the process, and Tribal Historic Preservation Officers (THPOs), Indian Indian tribal officials approved by the National Park Service to fulfill the role of the SHPO on Indian tribal lands. When an undertaking is on Indian tribal lands, the federal agency consults with the THPO, and if a tribe has no THPO, the agency consults with a designated Indian tribal representative and the appropriate SHPO. For undertakings off Indian tribal lands, the agency consults with all federally-recognized Indian tribes and Native Hawaiian organizations that attach religious and cultural significance to properties that may be affected by the undertaking.

Additional consulting parties include, but are not limited to, local governments, applicants for federal funds permits or licenses, and individuals and organizations with a demonstrated legal or economic interest in, or concern about historic properties that may be affected by the undertaking. The agency also has an obligation to inform and involve the public. Transportation agencies are generally involved in the Section 106 process as applicants for federal funds, permits, or approvals. Even though the FHWA may formally delegate their day-to-day Section 106 compliance activities to the transportation and other agencies, the latter is still considered a consulting party under the Section 106 process.

The Four Steps of the Section 106 Process

1. Initiate the Process
   The federal agency determines whether its project is an “undertaking” under Section 106 and if it could affect historic properties. If so, it begins consultation with the State Historic Preservation Officer (SHPO), Tribal Historic Preservation Officer (THPO), and other relevant parties.

2. Identify Historic Properties
   The agency defines the Area of Potential Effects (APE) and makes a good faith effort to identify historic properties within it. Unevaluated properties are assessed for eligibility for the National Register of Historic Places. If no historic properties are found or affected, the agency issues a “no historic properties affected” finding, concluding the process.

3. Assess Effects
   If historic properties are present and may be affected, the agency evaluates whether the impact is adverse—meaning it would harm the property’s historic integrity. If not, a “no adverse effect” finding is issued, ending the process.

4. Resolve Adverse Effects
   If adverse effects are found, the agency consults with stakeholders to avoid, minimize, or mitigate the impacts. The agreed-upon measures are documented in a legally binding Memorandum of Agreement (MOA). Once the MOA is signed and filed, and its terms are implemented, the Section 106 process is complete.

Flexibility in the Section 106 Process

Creative Mitigation

As noted above, the outcome of the Section 106 process is not predetermined. It is the interaction among the participants involved in this consultative process that determines the outcome (with the Federal agency making the final decision). As a result, there are many opportunities for creative and innovative approaches to fulfilling the requirements of Section 106. This is especially the case in resolving adverse effects.

Resolution of adverse effects is often treated as a mechanical process, using well-established, standard approaches such as archaeological data recovery (i.e. archaeological excavations) or photographing and documenting a historic building that will be destroyed as a result of an undertaking. Several state FHWA offices, transportation agencies, and SHPOs, however, are using non-standard, innovative approaches to resolving adverse effects. These approaches are often referred to as creative mitigation. Creative mitigation can result in better project and historic preservation outcomes, and has greater public benefit than standard approaches. Examples of creative mitigation include assisting in the development of local historic preservation plans and ordinances, developing educational materials and web sites, purchasing properties containing historic properties, or developing historic property management plans as a supplement to, or even in lieu of, standard mitigation.

Section 106 Program Alternatives

The four basic steps described in the previous section are the standard approach to Section 106 compliance. The ACHP’s regulation, however, allows Federal agencies to fulfill their Section 106 responsibilities through a variety of alternative approaches. These approaches are described in 36 CFR 800.14. FHWA has used two of these alternative approaches: programmatic agreements and exempted categories of undertakings.

Programmatic agreements (PAs) can be used to establish to establish a custom-designed Section 106 process for an agency program, for common types of undertakings (such as routine maintenance), and when a category or group of projects results in similar and repetitive effects on historic properties. PAs replace case-by-case Section 106 consultation and compliance with a programmatic approach. PAs are negotiated between the ACHP and Federal agency in consultation with SHPO(s), tribes, and other agencies. Public involvement is included as part of the development of these PAs.

A PA might, for example, provide a list of agency actions that are excluded from any additional Section 106 review because these actions have been repeatedly demonstrated to have no effect on historic properties. This type of PA is often referred to as a “minor projects PA.” A PA can also establish a standard treatment for dealing with historic properties that are repeatedly encountered during an agency’s undertakings, such as historical archaeological sites of a specific type and time period.

State FHWA division offices and transportation agencies have developed a wide variety of state-specific PAs. These range from PAs listing minor projects excluded from additional Section 106 review to PAs that delegate the majority of SHPO review authority (as delineated in 36 CFR 800.4 to 800.6) to the state DOT. Examples of these PAs can be found in the Center for Environmental Excellence’s Programmatic Agreements Library.

Interstate Highway Exemption

As the Interstate System approached its 50^th anniversary (2006), transportation and historic preservation officials realized that the system could be determined eligible for listing in the National Register, and thus subject to the requirements of Section 106, in addition to Section 4(f). As a result, federal transportation agencies would have to assess the affects of a large number of actions, involving all components of the Interstate. In March 2005, the ACHP, working with FHWA, approved an exemption that relieves Federal agencies from taking into account the effects of their actions on the Interstate Highway System. The ACHP Exemption Regarding Historic Preservation Review Process for Effects to the Interstate Highway System excludes certain individual elements and structures of the system that are already listed or already determined eligible for listing in the National Register, and elements and structures that have national or exceptional significance. FHWA also developed a state-by-state list of elements and structures of national or exceptional significance.

The exemption also states that “[e]ach Federal agency remains responsible for considering the effects of its undertakings on other historic properties that are not components of the Interstate Highway System (e.g., adjacent historic properties or archaeological sites that may lie within undisturbed areas of the right of way)…”

SAFETEA-LU (Section 6007) also exempts the majority of the Interstate Highway System from consideration as an historic site under Section 4(f) of the Department of Transportation Act. Section 4(f) will still apply to individual elements and structures of the system that are already listed or already determined eligible for listing in the National Register, and elements and structures that have national or exceptional significance. Additional information is available in FHWA’s Interstate Highway Exemption Guidance.

Additional Information on Section 106

For additional information, please see Section 106 Section on the ACHP website and the Center for Environmental Excellence by AASHTO’s Practitioner’s Handbook, Consulting Under Section 106 of the National Historic Preservation Act.

Section 4(f) of the Department of Transportation Act

Section 4(f) protects publicly owned parks, recreation areas, wildlife and waterfowl refuges, and historic sites of national, state, or local significance from being used for transportation projects—unless:

• No feasible and prudent alternative exists, and
• All possible planning is done to minimize harm.

What Qualifies as a Historic Site?

A historic site is any property listed or eligible for listing in the National Register of Historic Places, including archaeological sites that warrant preservation in place.

When Does Section 4(f) Apply?

• When a project uses land from a protected site, even if Section 106 finds no adverse effect.
• When a project causes constructive use—meaning it significantly impairs the features that make a site historically significant.

De Minimis Impacts

If a project’s impact is minimal (i.e., “no adverse effect” or “no historic properties affected” under Section 106), FHWA may issue a de minimis finding, satisfying Section 4(f) requirements. This requires:

• Consultation with SHPO/THPO and other parties, and
• Written agreement on the Section 106 findings.

Minimizing Harm

If land use is unavoidable, FHWA works with SHPO/THPO and other stakeholders to develop measures that reduce harm—often documented in a Memorandum of Agreement (MOA) under Section 106.

Programmatic Evaluations

FHWA offers programmatic Section 4(f) evaluations to streamline reviews for:

• Minor impacts to historic sites
• Use of historic bridges

Section 6(f) Land and Water Conservation Fund Act

The Land and Water Conservation Fund Act (LWCFA) of 1965 provides federal funding to states and agencies for acquiring and developing public outdoor recreation areas.

Key Provisions of Section 6(f):

• Permanent Protection: Land acquired or developed with LWCF funds must be used for public outdoor recreation in perpetuity.
• Conversion Restrictions: These lands cannot be converted to non-recreational uses without approval from the National Park Service (NPS).
• Replacement Requirement: If a conversion is approved, the land must be replaced with property of equal value, location, and recreational usefulness.

Overlap with Section 4(f):

• LWCF-funded lands are often public parks or recreation areas, making them subject to both Section 4(f) and Section 6(f).
• When planning mitigation for such properties, both statutes must be addressed.

Highway Projects and Section 6(f):

• If a transportation project affects Section 6(f) land, replacement land is required.
• Coordination with the State Liaison Officer and NPS is necessary for any proposed changes.

Bridge Preservation

Our nation’s historic bridges are visible examples of over 200 years of innovative structural engineering design and material technology. They range from rare 17^th-century bridges such as the Frankford Avenue Bridge in Philadelphia to examples of 20^th century technology like the 1931 George Washington suspension bridge in New York City, the 1932 concrete Rouge River Bridge in Oregon, and the 1920s and 1930s bascule bridges in downtown Chicago. Historic bridges are also a part of our country’s transportation infrastructure, and therefore, an important component of any effort to maintain and preserve the nation’s highway bridge transportation assets. Bridge preservation is a critical issue among transportation professionals.

Transportation agencies are required to consider the effects of their undertakings on a wide range or cultural resources, including historic bridges, as part of their responsibilities under Section 106 of the National Historic Preservation Act (NHPA) and the National Environmental Policy Act (NEPA). Historic bridges that are listed on or eligible for listing on the National Register of Historic Places are also considered Section 4(f) properties under the Department of Transportation Act. Compliance with these different statutes requires, as an initial step, determining whether or not a bridge is eligible for listing in the National Register and therefore considered historic. To address this issue, the FHWA’s Highway Bridge Replacement and Rehabilitation Program includes a provision requiring each state to complete a statewide historic bridge inventory. Most states have completed their inventories and several have recently or are currently updating their inventory.