Environmental Planning

Guidance for Federal-Aid Projects

Cultural Resources

Technical Guidance

This section of the Environmental Process Manual discusses how cultural resources are evaluated by the Historic Preservation Team (HPT) during project planning, design and construction. “Cultural resources” is a broad term that includes items, structures and sites of historical, archaeological, or architectural significance, typically older than 50 years.  The HPT is primarily responsible for ensuring that all ADOT construction projects consider project-related effects to significant historic and prehistoric cultural resources and that these undertakings meet the requirements of federal, tribal, and state historic preservation laws. Examples of laws and regulations that are typically addressed by HPT include the National Historic Preservation Act of 1966 (NHPA), the Antiquities Act of 1906, and Arizona Revised Statute § 41-862.  In the planning phase of a transportation project, HPT begins to determine what cultural resources occur within the area of potential effects (APE).  Each project involves a cultural resource assessment that includes a records search and if necessary, surveys within the APE to identify possible sites.

Section 106 Process

Federal, tribal, and state laws and regulations that grant protections to cultural resources and historic properties must be addressed in the cultural resources section of a NEPA document.  Section 106 of the National Historic Preservation Act requires federal agencies to take into account the effects of their undertakings on cultural resources included in, or eligible for inclusion in, the National Register of Historic Places.  It requires federal agencies to consider both the effects of a project and its reasonable alternatives on historic properties.  A federal agency whose project, funding or permit may affect a historic property, must seek ways to avoid, minimize or mitigate any adverse effects on historic properties.  In the event that a historic property or cultural resource will be affected by a project, a Section 106 consultation may be warranted. Consultation can also take place if there are no anticipated adverse effects.  A Section 106 consultation involves many entities including, but not limited to, ADOT, the State Historic Preservation Office (SHPO), tribes, land managing agencies, and FHWA.  The process typically involves: establishing the undertaking; initiating consultation; identifying the scope of work and the area of potential effects; identification of historic properties; determination of project effects; an assessment and resolution of adverse effects; and mitigation for adverse effects. There must be concurrence from all officials with jurisdiction that the proposed project satisfies local and federal laws in order for a proposed project to move forward. 

There are situations when there is no potential for a project to affect cultural resources or historic properties. In these situations, a cultural resources survey and agency concurrences are not required.  After evaluating project information, for a state-funded project, if the HPT Specialist determines that an undertaking has “no potential to effect” historic properties, a memo is issued to that effect.  For federally-funded projects, FHWA needs to provide written concurrence with the determination, and the HPT Specialist will obtain that concurrence prior to issuance of the memo.

Following are several flowcharts depicting the cultural resources evaluation process and documentation that is implemented during the planning, development, and construction of a transportation project:

Cultural Initiate Section 106 Process

Cultural Initiate Section 106 Process, cont'd

Cultural Historic Properties are within APE and may be Affected

Cultural Resolve Adverse Effects
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