Environmental Planning

Guidance for Federal-Aid Projects

NEPA Guidance

Categorical Exclusions

The Federal Highway Administration (FHWA) defines Categorical Exclusions (CE) as actions that based on past agency experience with similar actions, do not involve significant environmental impacts.

Actions that meet the criteria for CEs in 40 CFR 1508.4and 23 CFR 771.117(a) and (b) are approved as CEs. Both (c)-list and (d)-list categorical exclusions may be approved by ADOT under the CE Assignment Program.

These projects are exempt from the requirements to prepare an Environmental Impact Statement (EIS) or an Environmental Assessment (EA).


The following guidance documents will assist in preparing Environmental Documents:


The following template is available to be used for completing CEs:

Federal Highway Administration and the American Association of State Highway and Transportation Officials
Previous Highway Acts Affecting Change in Environmental Law
Environmental Assessments

FHWA's implementing regulations for NEPA are contained in 23 CFR 771, "Environmental Impact and Related Procedures." Regulations concerning Environmental Assessments (EA) are found at 23 CFR 771.119. An EA is prepared for an action that is not a Categorical Exclusion (CE) and does not clearly require the preparation of an Environmental Impact Statement (EIS), o where FHWA believes an EA would assist in determining the need for an EIS.

  • Environmental Overview Outline
    • This outline will guide the practitioner in preparing environmental overviews, which often precede the preparation of Environmental Assessments.
  • Environmental Assessment Guidance
    • This guidance is to be used on preparing Environmental Assessments. For additional guidance please call EPG at 602.712.7767 and ask to speak with a NEPA Planner.
  • Sample Cooperating Agency Letters
    • These two sample letters contain wording to invite federal agencies to participate as cooperating agencies in upcoming environmental investigations. One letter is for the US Army Corps of Engineers and the other is for the Apache-Sitegreaves National Forest.
NEPA Regulations and Processes
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