US-20 Ashton to SH-87 Junction PEL Study

Studies have shown that merely reducing a speed limit has little effect on the speed at which drivers will travel- they go at the speed that feels most comfortable to them. Furthermore, no published research findings have established any direct relationship between posted speed limits and crash frequency. The most severe crashes occur when the speed differential- the difference between a posted speed limit and the speed motorists are actually driving- is high. Reducing the limit below the warranted speed can actually be hazardous and unsafe.

Passing and turning lanes already exist on a large portion of US-20 from Ashton, through Island Park to the junction of SH-87. Extensive research and data have shown that these will not be sufficient to provide an adequate level of service on the road and keep travelers safe once projected growth is realized. Investments of this scale must be thoroughly studied and all the work done that will ensure they last a long time.  This study and the NEPA process through the future are looking toward a time when four lanes of travel on this section of US-20 will be essential. The work of the study and future efforts will make it so that once that time comes, the department will be ready to quickly move toward construction. They will only be implemented after further environmental analysis, and if or when predicted growth and traffic projections are closer to becoming reality.

An extensive amount of public meetings, workshops and more casual informative sessions have been held since the US-20 Ashton to SH-87 PEL process began. Based on input from the public early on, 59 alternatives were developed that have each been studied since then. During 2023-2024, ITD paused work on the more technical parts of the study to focus solely on public involvement. The department met with business owners, community interest groups, county and city leadership, with anyone who was affected by or showed interest in the project.

People voiced that they want to see projects done now that could improve safety immediately. As a result of that feedback, restriping on Ashton Hill was completed the summer of 2024 and the installation of a traffic signal at Yale-Kilgore Road is being installed in 2026.

ITD tried to better educate the public about environmental processes, when the improvements being considered would become reality, and all the factors that are involved in the study. At any given time, the department accepts and responds to public feedback on all ITD projects. In the name of safety, ITD will always look at data and growth projections to make sure we can keep Idahoans moving for a long time to come.

In the NEPA phase of this project, which is yet to begin, multi-use crossing opportunities at trails, pathways and bridges that intersect US-20 will be considered further. ITD will further study movement and wildlife migration with assistance and date provided from the Idaho Department of Fish and Game, the U.S. Forest Service and U.S. Fish and Wildlife Service. ITD is aware that this factor of planning for the future is of significant importance to those that have engaged in this project and will make sure options for wildlife crossing are considered as much as possible.

The study’s proposed improvements do vary by location, and the Idaho Transportation Department proposes expanding to four lanes with interchanges or wide medians throughout the corridor.

The alternatives that will be further evaluated in the NEPA process, which is anticipated will start in 2026 and beyond, are expected to change with further analysis and feedback from what is drawn on the map today. NEPA studies, preliminary design and final design will have to be done before construction can begin. None of what is seen throughout this PEL is happening next year, or for multiple years yet to come, and won’t be until it’s necessary. Clicking this link to the August 2024 online public meeting will give a general idea of what is being looked at in each of the different reaches of the US-20 Ashton to SH-87 PEL. These alternatives are the ones that have been selected to move forward after many suggestions and options from the public were studied as well.