US-20 Ashton to SH-87 JC

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Welcome — Your Input is Important!

The Idaho Transportation Department (ITD) is initiating a Planning and Environmental Linkages (PEL) process to look at ways to improve the US-20 corridor between Ashton and the SH-87 Junction. Increasing traffic is causing congestion and crashes. Improvements are needed to maintain a safe roadway and reliable connections to adjacent communities, Yellowstone National Park, and the region.

The purpose of the meeting is to share potential solutions to reduce congestion and improve safety on US-20 and gather your feedback as ITD continues the PEL study. Based on public feedback, ITD is taking another look at potential alternatives and will be screening Level 3 Alternatives over the next few months.

Project logo.

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Project Background

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.

With growth in traffic and tourism, it is time for ITD to find a solution to address safety and capacity concerns. ITD must find a solution that will handle increased traffic, meet driver expectations, and improve safety.

Project Overview and Orientation

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

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Public Input Received

An icon representing the public.

132 comments were received between May 25 – June 9, 2022. Many comments included more than one theme, making the total number of themes larger than the number of comments received.

181 public comments about design.

Feedback on the alternatives and design concepts.

  • Input on the Level 1 and 2 alternatives screening
  • Feedback on roundabouts, traffic signals, interchanges, overpasses/underpasses, and city bypasses
  • Opposition to a four-lane highway
  • Suggestions such as additional turn lanes, additional passing lanes, emergency pullouts, wider shoulders, and longer left-turn lanes

70 public comments about wildlife.

Input on preserving wildlife and their habitat.

  • Support for wildlife crossings in the project area
  • Opposition to wildlife crossings in the project area
  • Wildlife-vehicle collision concerns

37 public comments about safety.

Recommendations to lower the speed limit, enforce the speed limit better, and implement a consistent speed on US-20 through Island Park.

26 public comments about study process..

Observations regarding the study process.

26 public comments about community culture.

Experiences about the area and connections to community. Feedback include how roadway updates, including a four-lane highway, would affect the area and the community's culture.


Since 2021, ITD and FHWA have been working with the public, elected officials and agencies to develop a solution so that US-20 can continue to function safely with reduced congestion through 2050.

Through the PEL process the study team determined capacity needs, access management concepts and developed a wide range of alternatives. Based on feedback from the public, we have brought back the Alternating Passing Lanes (APL) to take a closer look and refined the intersections to include both at grade (AG) and grade separated (GS) intersections. We want to share the latest ideas and information with you as part of this online meeting.

Please take the time to share your thoughts and comments with us by using the comment form button in the top right corner. We will complete Level Screening in early 2023. Screeners will include local and elected officials, agency representatives and technical experts.

Your input will also help ITD and FHWA refine alternative concepts and advance the PEL process toward finding a solution for improving safety and reducing congestion on US-20 between Ashton and the junction of State Highway 87.

For more information, view the Level 1, Level 2, Level 3, and Multi-Use Crossing maps. If asked to sign in, please hit cancel and you will be entered into the site.

Screening consists of evaluating each alternative against set criteria such as:

  1. Access Management
  2. Environmental Resources
  3. Constructability
  4. Traffic Operations
  5. Safety

Alternatives that don't meet the criteria or have fatal flaws are eliminated. Alternatives needing refinement are modified to reflect stakeholder and agency suggestions or regulatory requirements.

ITD is seeking input on the Level 3 alternatives.


For a more detailed look, view the Ashton alternatives video

AC1 (AG)

Map of Ashton alternatives AC1.

AC2 (AG & GS)

Map of Ashton alternatives AC2.

AC3 (AG & GS)

Map of Ashton alternatives AC3.
Legend of elements found in the Ashton alternative maps.

PEL Process and Flexibility

Unlike the NEPA process, the PEL does not have time restrictions. This flexibility allows ITD to consider constructive input from the public and stakeholders on the range of alternatives. The PEL process allowed ITD the flexibility to pause the process to reconsider these ideas.

Process timeline of the PEL. Starting with Purpose & Need, followed by collection data, development alternatives (we are here), Alternative evaluation and public input, and finally consider input to add/change range of alternatives. If yes to considering the last step, the cycle starts back at develop alternatives. If no, move on to finalize PEL recommendations.

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In late summer 2022, stakeholders raised interest in ITD taking a closer look at two alternatives that had been previously removed from the process. ITD decided to pause the PEL process to do additional analysis to understand them as well as other Level 3 alternatives.

We are sharing a more detailed look at those reintroduced alternatives for public comment and questions. We will then carry them through the third level of alternatives evaluation and share the results as well as the recommendations for which alternative concept(s) should be carried forward into the NEPA process.

Multi-Use Crossings

ITD is evaluating:

  • Multi-use crossing opportunities at trails, pathways, and bridge locations that intersect US-20
    • Cyclists
    • Pedestrians
    • Snowmobilers
    • ATV/UTV riders
    • Equestrians
    • Snowshoers
    • Fishermen and other sportsmen
    • Hikers and other trail users
  • Wildlife crossing infrastructure
    • ITD is evaluating movement and wildlife migration information. Technical assistance is being provided by the U.S. Forest Service, U.S. Fish and Wildlife Service, and Idaho Fish and Game.
Photograph of pedestrian and bike trail at the side of a creek, both passing under a bridge. Below is a detailed graphic of the US-20 Highway bridge crossing a river with a wildlife bench, multi-use trail/path and the hight of the space under the bridge yet to be determined.

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PEL Process: How We Got Here

A schedule of the process. For detailed information, contact Micah Brown at the email,

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Summer 2021

PEL processes can help inform planning decisions, streamline the National Environmental Policy Act (NEPA) processes, and provide a platform for stakeholders to discuss and prioritize transportation issues and project implementation. Benefits include the following:

  • Developing a clearly defined purpose and need for alternative development and analysis, which is required by NEPA
  • Building collaborative working relationships with resource agencies and the public
  • Engaging with the Federal Highway Administration (FHWA), ITD, resource agencies, and local agencies
  • Identifying environmental resources that could require avoidance or minimization of impacts or lengthy environmental clearance processes
  • Improving the quality of information to make sound planning decisions and develop the most environmentally responsible and sustainable projects
  • PEL documentation adopted and referenced into future NEPA environmental review process

Oct. 12 & 13, 2021

ITD hosted two in-person public meetings and an online meeting in October 2021 to engage the public in the early stages of the PEL process. The in-person meetings were held at the EMS Building in Island Park on Oct. 12 and at the Ashton Community Center and Library on Oct. 13. The same materials were shared in an open house format so that attendees could ask questions and discuss issues with project staff members.

An online meeting was available from October 13 through October 29 on the project webpage at for those who could not attend in person. ITD asked that comments be submitted by the end of the day on October 29.

  • October 12 – 52 participants signed in. A few declined to sign in
  • October 13 – 59 participants signed in
  • Oct. 12 – 29 – 179 unique users visited the online meeting

Read the full PIM 1 meeting summary.

People gathered at a public meeting viewing information printed on foam board.

Dec. 7 & 8, 2021

ITD held two in-person workshops and a virtual workshop. Participants joined facilitated groups to brainstorm ideas and solutions for ITD to consider and helped identify issues that could be problematic or difficult to overcome. Several participants brought design ideas to share with the group and the project team identified 27 specific suggestions that related to alternatives throughout the project area.

  • Dec. 7 Workshop in Ashton – 25 participants
  • Dec. 8 Virtual Workshop – 17 participants
  • Dec. 8 Workshop in Island Park – 74 participants

Read the full PIM 2 meeting summary.

People sat around a table at a public meeting engaged in a conversation.

Dec. 2021 – Feb. 2022

Level 1 screening occurred in winter 2021 and Level 2 screening occurred in early spring 2022. Using input from the alternatives workshop, ITD developed 56 alternatives.

Following the Level 1 Screening meeting, 38 of the 56 alternatives were recommended for advancement to Level 2 analysis.

Screening included:

  • Reviewing and screening the alternatives against the evaluation criteria.
  • Completing a qualitative impact analysis to 11 environmental resource categories
  • Evaluating opportunities for multiuse crossings.
  • Evaluating ROW needs and the potential to modify the easement with the USFS and other state and federal land management agencies.
  • Evaluating local access roads connections; completing a review of land use planning and freight plans.

Level 1 and 2 screening committees included individuals representing ITD, local communities, State and Federal agencies, and consultant team members.

May 25 & 26, 2022

ITD hosted two in-person public meetings and an online meeting in May 2022 to share the results of the Level 1 and 2 screenings and engage the public for feedback. The in-person meetings were held in an open house format so that attendees could ask questions and discuss issues with project staff members.

An online meeting was available from May 26 to June 9 on the project webpage for those who could not attend in person. ITD asked that comments be submitted by the end of the day on June 9.

  • May 25 – 98 participants signed in at the Island Park EMS Building. A few declined to sign in.
  • May 26 – 55 participants signed in at the Ashton Community Center and Library.
  • May 26 to June 9 – 346 unique users visited the online meeting.

Read the full PIM 3 meeting summary.

December 5 & 6, 2022


The screening committee, made up of technical experts, local officials and agency representatives will share input and make suggestions about alternative refinements.

  • Impacts and benefits from each alternative will be provided to the screening committee for use in their evaluation.
  • Screening criteria specifically developed to determine safety, traffic operations, design performance, and environmental impacts and benefits will be evaluated.
  • Specific alternative refinements are likely to be made to avoid and minimize environmental impacts, accommodate access with fewer interchange structures, and limit impacts.
  • Your feedback from this Level 3 screening outreach will also be used to modify the alternatives considered in the final PEL report.

Spring 2023

ITD will present the results of Level 3 Alternatives screening.

Summer 2023

The PEL report will give a detailed overview of the process including alternatives screening and analysis, agency and local coordination, public involvement and environmental and technical analysis.

Future environmental clearance processes will be prepared in accordance with the requirements of NEPA (42 United States Code [U.S.C.] 4321, et seq.), 23 U.S.C. 139, CEQ regulations implementing NEPA (40 Code of Federal Regulations [CFR] 1500-1508), FHWA regulations implementing NEPA (23 CFR 771.101-771.139), and applicable federal, state, and local laws and regulations.

Planning products may be adopted by an agency conducting an environmental review (e.g., an Environmental Assessment [EA], Environmental Impact Statement [EIS], or other documentation) to meet NEPA requirements if the legal conditions for the PEL study are met during the transportation planning product development and the planning products meet PEL authority and NEPA requirements. Section 168 defines planning products to include Purpose and Need statements, preliminary screening of alternatives, elimination of unreasonable alternatives, and other planning decisions and analyses.

June 2023

When the PEL process is complete and the PEL report finalized, ITD and FHWA will work together to initiate the appropriate level of NEPA analysis. ITD and FHWA will analyze alternatives and there will be continued opportunities for public involvement and input.

Alternating Passing Lanes

What are Alternating Passing Lanes, or Two Plus One Highway?

An alternating passing lane or two plus one highway has alternating passing lanes added to a two-lane highway to allow drivers to pass slower vehicles. The passing lane alternates from one direction of travel to the other within a section of roadway allowing passing opportunities in both directions. A two plus one project can be introduced on an existing two-lane roadway where there is a significant amount of slow moving traffic, limited sight distance for passing, and/or traffic congestion that could be alleviated if motorists had the ability to pass slower vehicles on a more frequent basis.

Alternating Passing Lanes has several challenges including increased close calls and crashes at transition points.

Corridor Length = 45.3 Miles

Existing Passing Lanes
Northbound (NB) = 10.9 Miles
Southbound (SB) = 5.1 Miles

Map of possible and existing passing lanes along US-20.

Click image to enlarge

Design Alternatives

Challenges: Keeping slower traffic to the right.

Graphic of alternating passing lanes along the inside lanes.

Challenges: Crown location for snow plows, merging left and head-on perception.

Graphic of alternating passing lanes along the outside lanes.

Passing Lane Attributes

Graphic of alternating passing lanes along the outside lanes. Graphic of alternating passing lanes along the inside lanes. with a buffer area of 730 feet between transitions.

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For a more detailed look, view the Alternative Passing Lanes video

Grade Intersection/Interchange Details

At Grade Intersection

Detailed graphic of an at-grade intersection.

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  • Widened median allows for vehicle queuing at traffic signs refuge
  • Separated vehicle to vehicle conflict points for directional travel
  • Allows space for acceleration and deceleration lanes — less infrastructure maintenance


  • Potential high number intersection crashes

Grade Separated Interchange

Detailed graphic of a grade-separated interchange.

Click image to enlarge


  • Reduced overall number vehicle to vehicle of conflict points
  • Reduce intersection crashes
  • Accommodates multi-modal crossing


  • Increased maintenance of bridge structure
  • Visual impacts

For a more detailed look, view the Grade Intersections video

DRAFT Project Purpose and Need

DRAFT Project Purpose and Need

The Ashton to SH-87 Junction section of US-20 was originally built in the 1950s. The current roadway does not provide sufficient traffic flow or passing opportunities to accommodate growing traffic volumes. The roadway has exceeded its service life and requires improvements to roadway and drainage features. Reconstruction will provide the opportunity to include design elements that reduce the severity and frequency of crashes.


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

  • Improving capacity and Level of Service
  • Improving access management
  • Improving regional freight movement
  • Decrease severe crashes


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

  • Address existing deficiencies such as:
    • Travel time
    • Congestion
    • Delays
    • Safety
  • Prepare for future growth, economic development and tourism in the region
  • Increase freight mobility


When consulting with the public and resource agencies, ITD identified additional goals to be considered as the project is developed:

  • Integrate wildlife movement strategies in the corridor
  • Provide traffic calming measures or separation where the US-20 alignment runs through developed areas
  • Provide multiuse solutions that provide a range of options for recreational users

Environmental Considerations/11 Criteria

Alternatives will be evaluated through a screening process to determine how well they meet the project’s draft purpose and need. The screening process includes evaluating each alternative based on the following 11 environmental criteria.

  1. Visual Resources
  2. Agricultural and Forest Resources
  3. Air Quality
  4. Biological Resources
  5. Cultural Resources
  6. Geology and Soils
  7. Hazards and Hazardous Materials
  8. Hydrology and Water Quality
  9. Land use and Transportation Planning
  10. Noise
  11. Social and Economic Resources

Stay Involved

Please share ideas about the project. Public input is an important part of the decision-making process along with technical information and engineering best-practices.

For more information, visit the project page.


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:

ITD District 6 C/O Micah Brown
206 N. Yellowstone Highway
Rigby, ID 83442

While your comments are always welcome, they can be best utilized if received by Dec. 23, 2022.

Close comment form

While your comments are always welcome, they can be best utilized if received by Dec. 23, 2022.