Technical Guidance

CDOT uses a variety of different documents, manuals, and other guidance to complete its cultural resource reviews related to Section 106, Section 4(f), and the Colorado Historic Register Act. These have been developed at the federal, state, or agency-level and ensure CDOT reviews follow proper protocols in a consistent, thorough, and efficient manner.

Section 106

As stated in the regulation, Section 106 of the National Historic Preservation Act (NHPA) requires federal agencies to take into account the effects of their undertakings on historic properties and afford the Advisory Council on Historic Preservation (ACHP) a reasonable opportunity to comment on such undertakings [36 CFR 800.1]. CDOT carries out the responsibilities of Section 106 on behalf of the Federal Highway Administration (FHWA). For more information on the Section 106 process at CDOT, please see the resources below. For more information on the regulation itself, please see the Cultural Resources Links page of this website.

Procedures Manual

The CDOT Cultural Resources Procedures Manual describes the processes that CDOT Cultural Resource staff and consultants should follow when conducting a Section 106 review. 

Programmatic Agreement

Executed in 2014, the Section 106 Programmatic Agreement outlines the Section 106 process carried out by CDOT on behalf of FHWA.

Section 4(f)

Section 4(f) requirements stipulate that the Federal Highway Administration (FHWA) and other Department of Transportation agencies cannot approve the use of land from publicly-owned parks, recreational areas, wildlife and waterfowl refuges, or public and private historical sites unless there is no feasible and prudent alternative, or it is determined that the project will have a minimal impact on the resource. Several resources listed below aid in the understanding and implementation of the Section 4(f) regulations.

Section 4(f) Tutorial
Section 4(f) Policy Paper
FHWA Environmental Review Toolkit
AASHTO Practitioner’s Handbook #11: Complying with Section 4(f) of the US DOT Act

Colorado State Register of Historic Places Act

The Colorado State Register of Historic Places Act was passed in 1975 as a way to recognize and protect historic resources in Colorado. Similar to the Section 106 process, CDOT follows the guidelines Colorado State Register Act compliance to ensure that state-funded projects take into account the effects to historic resources. 


CDOT uses private consulting firms to conduct many of its cultural resource surveys and to complete focused research projects. Consultants hired to work on CDOT project must follow specific procedures and processes outlines in our Procedures Manual to ensure consistency across all CDOT projects. Consultants should also be aware of several different streamlining tools CDOT applies in project evaluation including the Advisory Council on Historic Preservation’s (ACHP) 2005 Interstate Highway Exemption, the ACHP 2012 Program Comment for Actions Affecting Post-1945 Concrete and Steel Bridges, CDOT’s 2016 Historic Highway Study, and CDOT’s multiple historic bridge inventories.

Consultant Submittal Guide

This document provides basic guidance and a checklist to assist consultants with planning and performing Section 106 and Colorado State Historic Register Act. A Consultant Submittal Guide (Word) is available for use. 

Cultural Resources GIS Deliverables

The CDOT cultural resources program is now requesting that consultants submit all completed GIS shapefiles associated with the site forms completed as part of historic property compliance in all CDOT regions. Please use this form for specific guidance.

CDOT Historic Sites Viewer

The Historic Sites Inventory is a GIS app that includes all historic and potentially historic built environment sites (no archaeological sites) recorded by CDOT or consultants within the last five years. Many of the sites do not appear in the SHPO's Compass database, so we request that all firms doing historic resource surveys for CDOT to consult this GIS tool. The CDOT Historic Sites Inventory is only available for use by qualified historians, meeting the Secretary of the Interior's Professional Qualification Standards for history, architectural history, or archaeology. If you would like access to the Viewer, please contact us.