US-20 — Ashton to SH-87

Skip to main content


Welcome — Your Input is Important!

Thank you for your interest in the US-20 Ashton to SH-87 JCT Planning and Environmental Linkages (PEL) process.

The purpose of this online meeting is to provide information about the PEL process, the Draft Purpose and Need , and potential alternatives for improving US-20 between Ashton and the SH-87 Junction.

Map of the project area highlighted. Project beginning near Ashton and Ending at SH-87.

Click image to enlarge

How to Navigate:

  • Click on the arrows on the bottom left and right side of your screen
  • Use the navigation menu at the left of the screen to revisit any part of the meeting
  • The pages are intended to be viewed in order to provide information about the study. However, you may use the tabs on the left side of the page to select any page

How to Participate:

  • Click through the slides to learn more about the project
  • Comments
    • Provide your comments at any time by clicking the “ COMMENT" button at the top right of the screen.
    • You can close the form to continue through the slides. Please make sure to hit the “Submit” button to confirm that your comment is sent to the project team.
  • The entire session should take less than 15 minutes to complete.


What is the US-20 Ashton to SH-87 JCT PEL?

The Idaho Transportation Department (ITD) is initiating this PEL process to analyze US-20 between Ashton and the SH-87 Junction and will look at ways to improve safety and reduce congestion.

Increasing traffic is causing congestion and crashes. Improvements are needed to maintain a safe roadway and reliable connection to adjacent communities, Yellowstone National Park, and the region.

The US-20 Ashton to SH-87 Junction PEL is a separate project from the Targhee Pass Environmental Assessment (EA). The EA was completed and a Finding of No Significant Impact (FONSI) was issued in late 2020. Decisions made as part of the EA will not be revisited during the Ashton to SH-87 Junction PEL project.

What is involved in the PEL Process?

Watch the video below to learn more about the steps that take place during a Planning and Environmental Linkages (PEL) Process.

Draft Purpose & Need

Draft Purpose

The purpose of the US-20 Ashton to SH-87 project is to enhance highway safety and operations by:

  • Improving capacity and Level of Service
  • Improving access management
  • Improving regional freight movement
  • Decrease the severity of the crashes
Traffic cone icon construction zone icon property damage icon

Draft Need

The need for improvements to the US-20 corridor is to:

  • Address existing deficiencies such as:
    • Travel time
    • Congestion
    • Delays
    • Safety
    • Meet modern design standards
    • Extend corridor design life
  • Prepare for future growth, economic development, and tourism in the region
  • Increase freight mobility
  • Evaluate multi-use solutions that provides a range of options for users

How does US-20 function now?

Increasing congestion is contributing to traffic crashes in the area.

20-year traffic volume from 2002 to 2021. According to the graphic, July has the highest traffic volume increase from 6,038 vehicles in 2002, to 10,534 vehicles in 2021
Heat map of crashes along project area corridor with densest areas at the SH-47 intersection and the Federal Hill area.

Click image to enlarge

How will project solutions be developed?

Watch this video to learn more about the data-driven approach ITD is taking to develop potential improvements for US-20.

How are Alternatives Evaluated?

Alternatives will be evaluated through a screening process to determine how well they meet the Draft Purpose and Need of the project.

  • Alternatives may include upgrades/changes to the current highway alignment.
  • Alternatives will consider new routes as well as changes to the existing highway including additional lanes, access control, and location specific safety improvements.

The screening process includes evaluating each alternative based on the following eleven environmental criteria.

Visual Resources
Agricultural and Forest Resources
Air Quality
Biological Resources
Cultural Resources
Geology and Soils
Hazards and Hazardous Materials
Hydrology and Water Quality
Land use and Transportation Planning
Social and Economics Resources

Where are we in the process?

Project schedule: We are at Public Meeting 1 in Fall 2021. The PEL process and Alternatives Development will continue through summer 2022. Alternatives Screenings 1 and 2 are scheduled for winter 2022 along with the second public meeting. Alternatives screening 3 is sheduled at the end of winter 2022. Public meeting 3 is scheduled for mid-spring 2022 along with PEL completion starting then through summer. Potential priorit improvement projects may happen through spring and summer 2022.

Click image to enlarge

Short-term Improvements to US-20

Click images to enlarge

Project corridor map highlighting short-term improvements.

Two short-term improvements have already been identified and scheduled as projects in the ITIP (Idaho Transportation Improvement Program).
As currently planned these projects could be constructed summer to 2024 or 2025.

Area map of short-term improvement at US-20 Elk Creek intersection.

US-20 Elk Creek Intersection (KN23240)

Area map of short-term improvement at US-20 Mack's Inn intersection.

US-20 Mack’s Inn Intersection(KN23241)

Green lines are proposed modifications to local road as described in the US-20 Corridor Plan (HDR 2006) and US-20 Corridor Plan Refresh (ITD 2016).

Stay Involved

ITD will actively engage a wide range of stakeholders interested in this corridor to determine how the corridor can be improved to best serve users. ITD will seek public input throughout the PEL process and public involvement will continue through future environmental analysis and design phases.

Public input will be an important part of the decision-making process and will be balanced with technical information and engineering best-practices. Project decisions will include a data driven process, meaning the team will use a scientific process to help develop and screen alternatives.


If you have questions please contact the project team.

Use the comment button at the top right of this meeting to view the comment form where you can submit comments. You can also submit comments via email to
or mail them to:

206 N. Yellowstone Highway
Rigby, ID 83442

While your comments are always welcome, they can be best utilized if received by October 29, 2021.

Close comment form

While your comments are always welcome, they can be best utilized if received by October 29, 2021.