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I-15/US-20 Connector

I-15/US-20 Connector Study


I-15/US-20 Connector Study

logoConstructed in the 1950s and 60s, the I-15 and US-20 interchanges in Idaho Falls have outlived their usefulness. The outdated infrastructure is affecting safety, mobility and economic opportunity in the city, county, and region.

The study includes six interchanges:

1I-15: Exit 118 – Broadway St. to Historic Downtown

2I-15: Exit 119 – US-20, Grandview Dr.

3US-20: Exit 307 – Lindsay Blvd.

4US-20: Exit 308 – Riverside Dr. to City Center

5US-20: Exit 309 – Science Center Dr.

6US-20: Exit 310 – Lewisville HWY

The first step will be a planning and environmental study, which is expected to take about 18 months.

I-15 US-20 Study Timeline

Four major goals for this study

  • Collect information about how the project might impact the area.
  • Make data from the environmental study accessible to all.
  • Determine short-, mid-, and long-term improvements as funding becomes available.
  • Develop a solid plan to provide safe and efficient travel for all users.

Idaho Falls Study Area Map

Sponsor Logos

Exit 119

A closer look at the Exit 119 Interchange in Idaho Falls.

I-15 Northbound off-ramp at Exit 119:

  • Has the highest volume of traffic of any I-15 ramp in Idaho.
  • During peak traffic times, more than 8,700 vehicles turn right to access U.S. 20.
  • Ramp traffic backs up and interferes with through traffic on I-15 Northbound.

Idaho Falls Exit 119 Speed Limits

Attempts to Improve Safety

  • ITD gradually reduces the speed limit on US-20 East of Exit 119.
  • Speed limit reduction appears to lessen the severity of crashes, but not necessarily decreased the frequency of crashes.


Sponsor Logos

The Idaho Transportation Department (ITD) is collaborating with the City of Idaho Falls, Bonneville County and other stakeholders on this project development.

Together, we will actively engage the public throughout the process to determine how to:

  • Improve the corridor
  • Better serve Idaho Falls
  • Grow the region


Join the Conversation
Several public outreach methods will provide many opportunities to give your input and improve the future of your community.

Communication Methods

For questions or comments: