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I-84, Franklin Road to Karcher Interchange

The Idaho Transportation Department is designing improvements to Interstate 84 between Caldwell and Nampa.

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Thank You

Thank you to everyone who participated in the I-84 Caldwell to Nampa online meeting!

Check back soon to see FAQs from the meeting and answers to your questions.

To view the videos from the online meeting, visit our downloads and resources section of the website.

You can also view the final design plans presented in the meeting here.

If you have any additional comments or questions, please email them to or call us at (208)334-8002.

Project Overview

The Idaho Transportation Department is designing improvements to Interstate 84 between Caldwell and Nampa. This project is necessary to improve safety and mobility on I-84 in Canyon County. The existing interstate can no longer accommodate current traffic volumes at peak periods of the day. As the Treasure Valley continues to grow, congestion in this corridor will increase.

The planned improvements include:

  • Widening I-84 to three lanes in each direction from the Franklin Road Interchange in the City of Caldwell to the Karcher Road Interchange in the City of Nampa.
  • Replacement and widening of six canal and lateral crossings.
  • Replacement of the Middleton and Ustick overpasses.
  • Two new noise walls along I-84 near Ustick Overpass and on the Franklin Road westbound on-ramp.
  • Replacement of the I-84 bridges over Linden Road.

Traffic Study

ITD has completed an in-depth traffic analysis as a part of this study. The traffic analysis considered projected traffic volumes between now and the design year 2045. The traffic analysis identified necessary improvements required to the interchanges to function in the future.

Environmental Study

In addition, ITD completed an environmental evaluation to help determine the needed improvements that will benefit  long-term safety and capacity on the corridor while minimizing impacts to the environment and adjacent properties

The environmental evaluation included field work, analysis, surveying and mapping, environmental research and reports, geological reconnaissance and materials report, preliminary hydraulic assessments, roadway drainage analysis and public involvement.

Visit the environmental website for I-84 Caldwell to Karcher here.

Community Input

Community input will play an important role in shaping the long-range plan for I-84 in Canyon County. Please watch for more information on a Public Meeting. To request text or email updates about this project, text 84CORRIDOR to 47177.

Questions about this project can be directed to or (208) 334-8002.

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