Overview
This project will:
- Replace the I-15 South Blackfoot Interchange.
- Improve on- and off-ramps.
- Make improvements to accommodate additional lanes on the interstate.
Improvements are being designed using an environmental evaluation, traffic and other technical data, surveying and public input.
We’re back with another I-15 update!
Are you curious about what’s being planned for I-15 between Fort Hall and Blackfoot? Check out the fall update video to learn about the status of three design projects:
- I-15 South Blackfoot Interchange (Exit 89)
- I-15 Exit 89 to Exit 93 Widening
- I-15 US-26/Blackfoot Interchange (Exit 93)
Background
The I-15 South Blackfoot Interchange has served motorists since 1961. Since then, eastern Idaho’s population and traffic volumes have greatly increased and interchange design standards have changed.
For these reasons, it necessary to develop a design that will increase capacity and mobility, improve safety and update the interchange to meet current design standards.
Anticipated growth
Eastern Idaho’s traffic volumes have greatly increased since the construction of the South Blackfoot Interchange, and growth is expected to continue. The Average Daily Traffic (ADT) count at this interchange is expected to almost double by 2051. The project team’s goal is to design an interchange that will serve the growing needs of eastern Idaho for years to come.
2023 – 27,500 ADT
2051 – 53,230 ADT
Next steps
ITD hosted two public open houses in 2025 about three projects along I-15 between Fort Hall and Blackfoot:
- I-15 South Blackfoot Interchange (Exit 89)
- I-15 Exit 89 to Exit 93 Widening
- I-15 US-26/Blackfoot Interchange (Exit 93)
The project team is reviewing public feedback and will continue the design process for each project.
Stay informed & provide input
Input from the community is important to the success of this project. ITD will provide multiple opportunities for public input during the design process.
To remain informed about upcoming opportunities, learn more and to provide feedback:
- Click here to sign up for email updates.
- Call (208) 252-5553
- Email info@pocatellotoidahofalls.org
Timeline
-
2024
Gathered technical information to help develop preliminary design plans
-
2024-2025
Developed preliminary design plans
-
2025-2027
Develop final design plans
-
2028
Construct improvements (depending on TECM bond funding)
Frequently Asked Questions
The I-15 bridges over US-91 and the Union Pacific Railroad are reaching the end of their service life and need to be replaced. To improve safety and mobility on these structures, it is necessary for ITD to replace the interchange with a design that has increased capacity and meets current design standards.
The project team will develop and evaluate several design options that may differ from the current interchange in a variety of ways. However, ITD has specific improvement goals including:
- Lengthening ramps to improve safety.
- Increasing vertical clearance to allow for mega loads.
- Adjusting the interchange to accommodate future additional lanes on I-15.
ITD will evaluate several interchange design options, including designs with and without curved ramps. If a design with curved ramps is selected as the preferred design option, the design will be improved to meet current safety and operational standards.
The design of this project is utilizing state and federal funding. The construction of this project is planned to utilize TECM bond funding.
An environmental evaluation is a process that helps the project team determine how design options will impact the human and natural environment around the project area. The data collected during this environmental evaluation will inform the project team as they work to develop a design that balances the needs of the environment with the public’s need for a transportation system that prioritizes safety, mobility and capacity.