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ITD Projects Southwest Idaho U.S. 20/26 Corridor Study, I-84 to State Line

U.S. 20/26 Corridor Study, I-84 to State Line

Study Facts
Key Number: 09972
Project Number: P083530

The purpose of the U.S. 20/26 Corridor Study is to develop a medium range (through 2020) plan that identifies current and future highway needs for more than 14 miles of U.S. 20/26 running from I-84 near Caldwell west to Nyssa, Oregon and the Snake River. The highway overlaps U.S. 95 for eight miles from east of Parma to Anderson Corner Road - the corridor study for that section is addressed in the ongoing U.S. 95 Corridor Study.

The Corridor Study is being done to comply with Idaho Transportation Department Board policy, which is also consistent with federal planning guidance. The study and subsequent adopted plan will be used to chart U.S. 20/26 road improvements from I-84 to the state line in the Statewide Transportation Improvement Program (STIP).


The completed plan will include:

• A 10-year plan for the corridor.

 • Identification of corridor priorities.

• Identification of existing and projected environmental, roadway, and land use conditions.

• Analysis of future travel demand and performance in the corridor.

• Analysis of accidents and recommendation of safety features including access management.

Design Guidelines

Sample urban and rural cross-sections of the highway will be illustrated.  Any projected capacity improvements that require a cross-section different from the current samples will also be illustrated. Features will include:

• Number of lanes

• Lane width

• Shoulder width

• Side slopes

• Curb, gutter, and sidewalks for urban cross-sections

Environmental Review

The National Environmental Policy Act (NEPA) requires that an environmental review be completed before right-of-way can be acquired with federal funds. The U.S. 20/26 Corridor Study is not programmed to recommend or fund purchase of right-of-way.  Therefore, ITD will not complete a NEPA-level environmental review. However, an Environmental Scan will be conducted to provide a baseline survey which includes a qualitative analysis of the current human environment. The human environment includes aspects of the natural environment, built environment, and human health.  Constraints that may have a limiting factor in roadway width and placement of the highway section will also be identified.

Study Background

U.S. 20/26 is a major farm-to-market road serving agriculture and quarrying industries in western Canyon County. Cross-state access is directly provided to Nyssa and connecting access is provided via Highway 18 to Adrian, Oregon. The majority of the highway is two-lane rural with a 65 mph speed limit. 

Make Comments
The Idaho Transportation Department values your input. Submit written comments using one of the forms below or contact for more information.
    •Email Us please include your name and address
    •Download a comment form (word doc)


Mark Wasdahl, Project Manager
(208) 334-8344

Compliance with Title VI of the Civil Rights Act
The Idaho Transportation Department (ITD) is committed to compliance with Title VI of the Civil Rights Act of 1964 and all related regulations and directives. ITD assures that no person shall on the grounds of race, color, national origin, gender, age, or disability be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any ITD service, program, or activity. The department also assures that every effort will be made to prevent discrimination through the impacts of its programs, policies, and activities on minority and low-income populations. In addition, the department will take reasonable steps to provide meaningful access to services for persons with Limited English Proficiency.

Meeting Materials

Workshop Invitation

Display Boards

Powerpoint Presentation

Meeting Comments
News Releases

10/20/2009 - Public Invited to comment

ITD Public Involvement
P.O. Box 7129
Boise, ID 83707-1129
Phone: (208) 334-8119
Fax: (208) 334-8563
TTY/TDD Users: Dial 711 or
(800) 377-3529 to use Idaho Relay System

Page Last Modified: 11/25/2013 3:23:25 PM

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Idaho Transportation Department
3311 W. State Street P.O. Box 7129
Boise, ID 83707-1129
(208) 334-8000