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Section 106 Process for Project Managers

1. Introduction

Before KYTC begins construction on a project that involves the use of (1) federal property, (2) federal funding, or (3) the acquisition of federal permits, Section 106 of the National Historic Preservation Act (NHPA) mandates the agency examine whether the project will impact historic sites and archaeological resources. Examples of historic properties include prehistoric or historic sites, districts, buildings, structures, and objects listed or eligible for inclusion on the National Register of Historic Places (NRHP). Section 106 does not apply to state-funded projects, unless a project requires a federal permit or approval. If analysis finds a project will impact a historic site, KYTC must take steps to avoid, minimize, or mitigate those impacts.

The Federal Highway Administration (FHWA) is the lead agency responsible for verifying KYTC’s compliance with Section 106. However, a programmatic agreement signed in 2011  delegated responsibility for completing the Section 106 process to the Cabinet.

This article provides a high-level overview of the Section 106 process that KYTC project managers (PM) can use to navigate the Section 106 process and the associated facets of the Section 4(f) process, and collaborate successfully with Division of Environmental Analysis (DEA) subject-matter experts (SME). It describes and presents examples of mitigation undertaken to compensate for impacts to aboveground and belowground cultural and historic resources.

PMs can apply the following best practices to streamline the Section 106 process and accelerate project delivery:


  • If possible, avoid project alignments that will impact historic properties.
  • Maintain robust communication with DEA SMEs throughout project development. SMEs have the knowledge to help PMs handle Section 106 and identify options for avoidance, minimization, and mitigation.
  • If the project footprint or scope are modified, get in touch with the DEA SME as soon as possible so they can determine whether KYTC’s obligations under Section 106 and/or Section 4(f) have changed.
  • When in doubt about how to address issues related to Section 106 or Section 4(f), ask for guidance and assistance from DEA SMEs — their job is to help.

2. Review of Section 106 Process

The purpose of the Section 106 process is to determine whether projects that receive federal funding, require federal permits, or occur on federal lands will impact eligible historic properties. Some project types generally do not impact historic properties and are thus exempt from review under the Section 106 programmatic agreement (Section 4 lists these projects). However, the Cabinet must certify a project has no potential to affect historic properties by completing the KYTC Archaeological Investigation Form.

The Handbook for Implementing Section 106 of the NHPA differentiates requirements for small-scale and large-scale projects.


  • Small-scale projects are those whose impacts are evaluated using one of the following environmental document types: Categorical Exclusion (CE) for Minor Projects, CE Level 1, and CE Level 2.
  • Large-scale projects tend to involve major reconstruction or new construction, are complex, elicit public controversy, and are more likely to cause environmental impacts. This includes projects evaluated using one of the following environmental document types: CE Level 3, Environmental Assessment (EA), or Environmental Impact Statement (EIS).

2.1 Initiating Section 106 Consultations

Section 106 mandates that interested parties be given the opportunity to provide input into identifying historic properties, evaluating how a project will impact these properties, and deciding on appropriate strategies to resolve adverse impacts. 36 CFR 800.2(c) specifies two groups of consulting parties: 

  • Consulting parties involved in most Section 106 processes. This includes the State Historic Preservation Officer (SHPO); Tribal Historic Preservation Officers (THPOs); Indian tribes recognized by the federal government; Native Hawaiian organizations; local government representatives in the jurisdiction where a project is located; applicants for federal assistance, permits, licenses, and other approvals; and the National Park Service.
  • Stakeholders that have a clear interest in a project due to their legal or economic interest in affected properties, or their concern with how a project will impact historic properties. This includes individual citizens, local historic preservation organizations or interest groups, and federal or state government agencies with an interest in the project. To be recognized as a consulting party, stakeholders in this category must submit a formal written request to KYTC.

When a stakeholder requests consulting party status, DEA and the SHPO review the request and make a recommendation. If DEA and the SHPO do not agree on whether to grant a stakeholder’s request, FHWA makes the final determination, potentially with input from the American Council on Historic Preservation (ACHP).

On most projects, DEA is responsible for managing coordination with consulting parties.

2.2 Define the Area of Potential Effect (APE)

The APE encompasses locations where a project may directly or indirectly impact the character or use of historic properties. The Section 106 programmatic agreement offers guidance on delineating APEs for small- and large-scale projects.


  • Small-scale projects: For projects on existing corridors, SMEs screen for aboveground resources by inspecting properties that lie partially or entirely within a 300-foot-wide corridor (150 feet on each side of the proposed centerline). The corridor width may be widened or narrowed to account for project-specific contingencies. For archaeological resources, the APE typically encompasses the limits of the proposed right of way (ROW), easements, staging areas, and other locations where project activities may disturb the ground.
  • Large-scale projects: KYTC consults with the SHPO to define the APE. For aboveground resources, the APE typically encompasses the proposed project’s viewshed. For archaeological resources, it usually includes the limits of the proposed ROW, easements, staging areas, and other areas where project activities may disturb the ground.

2.3 Identifying Historic Properties

Cabinet SMEs or consultants identify historic properties within the APE that are listed on or are eligible for the NRHP. Sites eligible for inclusion on the NHRP are treated in the same manner as listed sites. On small-scale projects, District Environmental Coordinators (DECs) can engage in preliminary work (e.g., demonstrating that soils have already been disturbed, using standard data sources to determine if structures at least 50 years old are present).

2.4 Evaluating Impacts on Historic Properties

SMEs evaluate historic properties within the APE’s footprint to determine if a project will (1) directly or indirectly alter characteristics that qualify them for inclusion on the NRHP and/or (2) harm the integrity of the property’s location, design, setting, materials, workmanship, feeling, or association.

The significance of sites greater than 50 years old is evaluated by determining if they are associated with a historic event or a person who is historically consequential, if it represents the work of a master or is an exemplar of a particular architectural/ structural style, or if significant scientific data are located on the property. Section 3 provides details on the types of investigations performed for archaeological and cultural/architectural resources.

An assessment concludes with one of three determinations: No Adverse Effect, No Historic Properties Affected, or Adverse Effect. If a project is going to impact a property but not alter its eligibility for the NRHP, the determination is No Adverse Effect.

  • If a small-scale project will produce adverse effects, KYTC notifies FHWA. The Cabinet works with FHWA to examine project alternatives or modifications that can eliminate or minimize the effects. If effects cannot be avoided, the Cabinet works with FHWA, the SHPO, and other consulting parties to resolve the issue.
  • If a large-scale project will produce adverse effects, KYTC notifies FHWA before consulting with the SHPO. The PM and project team then explore strategies to avoid, minimize, or mitigate the effects.

2.5 Section 4(f)

Section 4(f) of the U.S. Transportation Act of 1966 directs agencies to consider the impacts of federally funded transportation projects on publicly owned parks, recreation areas, wildlife and waterfowl refuges, and historic sites eligible for or listed on the NHRP. Unlike Section 106, Section 4(f) directs agencies to make a concerted effort to avoid the use of cultural resources and to undertake planning that minimizes harm to historic sites resulting from their use.

Under Section 4(f), use is defined as (1) the permanent incorporation of Section 4(f) properties into a transportation facility; (2) temporary occupancy of Section 4(f) properties that produces adverse outcomes; or (3) constructive uses that affect a property’s protected attributes, activities, or features.

Section 4(f) deals only with the use or occupancy of historic sites, while Section 106 is concerned with evaluating whether a project has the potential to adversely impact historic properties. Unless an archaeological site requires preservation in place, it is not subject to review under Section 4(f).

Perhaps most importantly, Section 4(f) is a substantive law. As such, FHWA or other USDOT agencies cannot approve the use of Section 4(f) properties unless there is no feasible or prudent alternative, or if FHWA concludes use of the properties will have a de minimis impact. A de minimis impact is one that does not adversely affect the activities, features, or attributes of Section 4(f) properties (the dictionary definition of de minimis is lacking significance or importance — basically, a minor effect).

Historic properties that qualify for protection under Section 4(f) are identified through the Section 106 process. For these historic resources, Section 106 findings directly inform determinations made under Section 4(f):

  • If the Section 106 assessment results in a finding of No Historic Properties Affected, the Section 4(f) evaluation results in a finding of No Use.
  • If the Section 106 assessment results in a finding of No Adverse Impact and the project entails use of a historic resource (e.g., minor acquisition), the Section 4(f) evaluation results in de minimis finding.
  • If the Section 106 assessment results in a finding of Adverse Impact, KYTC must perform an individual Section 4(f) evaluation, except when a programmatic evaluation is carried out.

KYTC has four pathways to achieve compliance with Section 4(f): 

  • Finding of No Use
  • de minimis impact determination
  • Programmatic Section 4(f) evaluation
  • Individual Section 4(f) evaluation

FHWA has issued programmatic evaluations that apply to five project types — those which (1) use historic bridges, (2) have minor impacts on parks, recreation areas, or refuges; (3) have minor impacts on historic sites; (4) construct independent walkways or bikeways; (5) produce a net benefit for a Section 4(f) property. Most often, the Cabinet uses the programmatic evaluation for historic bridges.

Compared to individual Section 4(f) evaluations, programmatic evaluations are less time consuming and require less documentation. Individual Section 4(f) evaluations can sometimes take years and typically require more intensive mitigation.

The PM and project team are responsible for evaluating whether any alternatives directly impact Section 4(f) properties and if temporary impacts meet the criteria for temporary occupancy.

2.6 Resolving Adverse Effects

KYTC, FHWA, and all consulting parties work together to resolve adverse effects through avoidance, minimization, or mitigation. The Cabinet strives to resolve adverse effects through avoidance or minimization. For example, modifying a project’s footprint, altering the design of a bridge or road, or relocating a historic structure (e.g., a rock wall) can help KYTC achieve a No Adverse Effect determination.

When adverse effects are resolved through mitigation, KYTC develops a memorandum of Agreement (MOA) that outlines its mitigation plans. The MOA describes the historic property and its importance, project impacts, parties that the federal agency has consulted with, and steps that will be taken to carry out mitigation. In some cases KYTC legal counsel review MOAs, particularly those which are complex or incorporate unique elements. The MOA must be signed by the Cabinet, FHWA, SHPO, ACHP (if applicable), other parties tasked with implementation, and other parties who played a role in resolving the adverse effects. MOAs must be fully executed before FHWA approves an environmental document (CE, Finding of No Significant Impact (FONSI), Record of Decision (ROD)).

If the federal agency or any of the by-right (KYTC, SHPO, Tribes) or invited (citizens, other governmental agencies, or organizations with a vested interest in the project or the property) signatories to the MOA cannot reach an agreement, the final decision on mitigation rests with the lead federal agency. The Section 106 process does not guarantee an outcome.

2.7 Documentation

For exempt projects (see Section 4), KYTC reports findings to FHWA and the SHPO each quarter. For small-scale projects, the Archaeological and Historical Architectural Investigation Forms, along with supporting documentation, are submitted to the SHPO, which has 30 days to comment on findings. Documentation for large-scale projects is more extensive and should adhere to SHPO guidelines.

2.8 Post-Review Discoveries

Sometimes historic properties are not found during the Section 106 process, coming to light only after construction has begun. When this occurs, construction in the affected area must be halted until KYTC contacts the SHPO and relevant consulting parties (including Indian tribes) and then evaluates whether impacted properties are eligible for the NRHP. The Cabinet should take all efforts to avoid, minimize, or mitigate effects to historic properties.

Similarly, if human remains or evidence of human remains are found, all project work in the area must stop. Remains and other materials on the site are then secured, with KYTC notifying law enforcement officials and the country coroner. If the remains are not associated with a modern crime scene, the Cabinet coordinates with the Kentucky Heritage Council and Kentucky Office of State Archaeology to pursue further investigation. If an archaeologist concludes the site contains prehistoric artifacts or human remains, FHWA begins the consultation with relevant Indian tribes. Remains or objects deemed not of American Indian origins may be excavated or relocated once FHWA issues approval.

2.9 Mitigating Adverse Effects

This section briefly describes some of the mitigation actions KYTC can or has taken to compensate for impacts to Section 106 properties.

2.9.1 Mitigating for Archaeological Resources

Mitigation of archaeological sites is uncommon, with fewer than 1% of sites that KYTC identifies requiring mitigation. Typically, mitigation refers to excavating an archaeological site and retrieving as much scientific data as possible.

Analysis and interpretation of data are presented in Phase III reports. Most archaeological reports are not released publicly. If they are, the Cabinet redacts identifying information. But when the Cabinet spends federal dollars to excavate an archaeological site it must demonstrate a public benefit. To satisfy this requirement, KYTC produces materials such as brochures that present findings in a non-technical manner, full-length documentaries, and even educational materials that can be used in the classroom.

Alternative mitigation can be used if excavation is not a feasible mitigation option or when a significant archaeological site is accidentally impacted (e.g., construction occurs in an area that has not been cleared under Section 106; an area inside the project footprint is affected before archaeological investigations are finished). Examples of alternative mitigation include the production of documentary features, funding the annual Living Archaeology Weekend in Daniel Boone National Forest, funding The Archaeology Channel to expand distribution of documentaries, developing the Discover Kentucky Archaeology online portal, or creating Esri StoryMaps. All forms of mitigation have the goal of delivering information on archaeology to the public in formats that are readily accessible.

2.9.2 Mitigating for Cultural Historic Resources

Mitigation varies by the type of resource impacted and the criteria which designate a property as historic. Examples of mitigation for programmatic Section 4(f) impacts to bridges include State Level Documentation (SLD), context studies, and funding museum exhibits. SLD may consist of a report that includes as-built renderings of bridge plans or drawings produced by cultural historians. The goal of SLD reports is to situate a bridge within its historical context. Two examples of these reports are one on the historic context of the interurban railroad in Jefferson County and a historic resources document completed as part of the Louisville-Southern Indiana Ohio  River Bridges Project.

Individual Section 4(f) evaluations tend to be reserved for large, complex projects in densely populated areas (e.g., Brent Spence Bridge, Lexington’s Newtown Pike extension). Mitigation can assume different forms. On the Brent Spence Bridge project, KYTC is preparing a SLD focused on historic properties that will be removed, funding façade grants, and updating the nomination form for the Lewisburg Historic District. In Lexington, mitigation entailed developing a SLD for the Southern Railway depot and funding improvements to the Carver Center. KYTC has also worked with local museums to develop transportation-related exhibits.

3. Permitting Aboveground and Belowground Cultural Resources Assessments

    This section reviews processes for evaluating aboveground resources (i.e., buildings, structures, objects) and belowground resources (i.e., archaeological features). Because PMs are not responsible for conducting these investigations, material is presented at a high level. Tables 1 and 2 capture what contributions PM make on different types of investigations (if any).

      Table 1 Documentation of Archaeological Resources and PM Responsibilities
      Survey Type Description PM Responsibilities
      • Identifies where project construction may impact archaeological resources.
      • Methods: record reviews; analysis of historical mapping; review of topography, soils, and geology; site visit; interviews.
      • Findings used for project-level planning studies and to compare corridors and alignment.
      • Not meant to address Section 106 decision making.
      Works with DEC to coordinate document review.
      Phase I Intensive Survey
      • Identifies sites that may be impacted by construction and which are eligible for the NRHP.
      • Methods: record reviews, field investigations (e.g., surveys, shovel probes, machine trenching, machine coring).
      • Findings may be used to recommend whether a site should be included on the NCHRP and to compare project alternatives or the impacts of preferred alternatives.
      • Results dictate whether Phase II or Phase III investigations are needed.
      • Reports are reviewed by the SHPO and/or FHWA, which can take up to 30 days.
      • Phases I and II may be combined into one field investigation.
      Phase II Testing
      • Conducted when Phase I does not reach a conclusion about NHRP eligibility and project alternatives cannot avoid any of the sites.
      • Determines whether a site is eligible for the NRHP and used to inform an archaeological data recovery plan.
      • Methods: archival research, intensive fieldwork (e.g., surface collection, shovel probes, trenching, remote sensing).
      Works with DEC to coordinate document review.
      Phase III Data Recovery
      • Done when a project will adversely impact a site listed in or eligible for the NHRP and mitigation through excavation is an appropriate treatment because avoidance or preservation in place is not an option.
      • Methods: archival research, intensive fieldwork (e.g., surface collection, shovel probes, trenching, remote sensing).
      • Must be finished before approval of the final NEPA document is approved.
      Works with DEC to coordinate document review.
      Table 2 Documentation of Cultural/Architectural Resources and PM Responsibilities
      Review Type Description PM Responsibilities
      Historic Architectural Review
      • Done early in project planning and development to locate aboveground sites in the project area that are at least 50 years old and identify historic sites eligible for the NRHP.
      • Methods: windshield survey, records search, photography.
      • Only architectural surveys can determine whether a property meets NRHP’S 50-year age criterion.
      Works with project team to review documents and determine how findings will impact project-related decision making.
      Historic Architectural Survey
      • Identifies historic architectural sites eligible for the NRHP that projects may experience direct or indirect impacts.
      • Methods: records search, review of previously surveyed sites and historical maps, archival research, field investigations.
      • Describes on project effects on each NRHP-eligible property.
      • Evaluates impacts of project alternatives and offers strategies to mitigate adverse effects.
      Coordinates document review with project team and DEC.

      4. Exempted Project Types

      The Section 106 programmatic agreement exempts some small-scale projects from review (see bullet list below) because they are unlikely to impact historic properties. If a project will not impact historic properties, KYTC has no further obligations under Section 106. However, if a project can potentially impact a historic property, the impacts are documented on a KYTC Archaeological and Historical Architectural Investigation Form, a Kentucky  Heritage Council Survey Form, and/or Office of State Archaeology Forms.

      • General highway maintenance (e.g., filling potholes, crack sealing, mill and resurfacing, joint grinding/milling)
      • Guardrail replacement that does not require new bank stabilization
      • Installation and maintenance of highway signs, pavement markings, or contemporary fencing within existing  ROW
      • Pavement marking or line-painting projects
      • Spraying herbicides within existing ROW
      • Improvements to existing KYTC/county maintenance facilities
      • Study-type projects (e.g., feasibility studies)
      • Approval of utility installations along or across a transportation facility that do not drain wetlands
      • Acquisition of scenic easements
      • Transfer of federal lands to another federal agency pursuant to USC 317 when the subsequent action is not an FHWA action.

      4.1 Small-Scale Projects with Potential to Affect Historic Properties

      The Handbook for Implementing Section 106 lists undertakings typically processed as small-scale projects. The project types listed below typically qualify as small-scale projects and tend to have few, if any, impacts.

      Bridges and Structures

      • Culvert and structure replacement/reconstruction requiring minimal ROW acquisition
      • Bridge rehabilitation, reconstruction, or replacement
      • Bridge deck overlays, bridge deck replacements, bridge painting projects


      • Track and rail-bed improvements, maintenance, or acquisition
      • Replacing at-grade railroad crossings with grade separation. Removing railroad grade separation structures.
      • Constructing or converting rail storage and maintenance facilities in industrial/transportation landscapes. Buildings must comply with existing zoning and noise impacts must be minimal.
      • Rehabilitating, reconstructing, or converting rail/bus buildings, and ancillary facilities in a way that requires little additional land and does not significantly increase users.

      Roadway / Highway

      • Replacing traffic signals within existing ROW
      • Highway safety, truck escape ramp, or traffic operation improvement projects
      • Highway modernization accomplished through resurfacing, restoration, rehabilitation, reconstruction, or adding auxiliary lanes. FHWA approval is required for adding through lanes on interstates or freeways.
      • Modifying an existing interchange. Constructing a grade-separated interchange to replace an at-grade intersection. Not applicable to projects on the interstate system.
      • Installation of ramp metering control devices and lighting
      • Approvals for changes in access control to the National Highway System or limited access ROW. FHWA must approve federally funded projects that require changes in access control.
      • Tower lighting projects
      • Constructing new truck weigh stations or rest areas

      Aesthetic and Multimodal

      • Installing new fencing, signs, small passenger shelters, traffic signals, and railroad warning devices if no significant land acquisition or transportation facility disruption occurs
      • Beautification or facility improvement projects (e.g., landscaping, curb and gutter installation, placement of park benches, decorative lighting installations)
      • Improving or constructing bicycle and pedestrian lanes, paths, or facilities.
      • Noise wall installation


      • Constructing new bus storage and maintenance facilities in industrial/transportation landscapes. Buildings must comply with existing zoning and be on or near a street with adequate capacity.
      • Constructing KYTC storage and maintenance facilities in industrial/transportation landscapes. Buildings must comply with existing zoning and noise impacts should be minimal.


      • Wetland and other mitigation projects
      • Disposal of excess ROW or for joint or limited use of ROW where the proposed use would have minimal or no adverse social (including highway safety), economic, or environmental impacts.
      • Disposal of excess ROW wholly contained in recent Major Project Acquisitions.

      5. Resources

      KYTC Archaeology Homepage — Provides a brief overview of the archaeology process with links to legislation and regulations.

      KYTC Cultural Resources Homepage — Describes the Section 106 and includes links to external organizations, documents, legislation, and regulations.

      KYTC Section 106 Programmatic Agreement — Original text of the Section 106 programmatic agreement signed by the Cabinet, FHWA, ACHP, and Kentucky’s SHPO.

      KYTC Section 106 Handbook — Offers detailed guidelines on working through the Section 106 process under the programmatic agreement.


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