Overview
Interstate 15 serves as a major transportation corridor through eastern Idaho. These improvements will increase capacity and improve safety to serve the region’s growing transportation needs for years to come.
Crossover traffic patterns
Nightly crossover traffic patterns will occur on I-15 near the Fort Hall Interchange (Exit 80) beginning Thursday, June 25. Crossover traffic patterns will create a work zone for crews to safety remove lead-based paint from the abandoned railroad bridge over I-15.
What to expect during crossover traffic patterns:
- I-15 will be reduced to one lane in each direction from south of the Fort Hall Interchange to north of the abandoned railroad bridge.
- On Thursday and Friday nights (June 25 and 26) from 7 p.m. to 6 a.m., both northbound and southbound I-15 traffic will use the southbound lanes of I-15.
- On Saturday night (June 27) from 7 p.m. to 6 a.m., both northbound and southbound I-15 traffic will use the northbound lanes of I-15.
- Crossover traffic patterns will not occur Sunday night.
- Monday and Tuesday nights (June 29 and 30) from 7 p.m. to 6 a.m., both northbound and southbound I-15 traffic will use the northbound lanes of I-15.
- Speed limits will be reduced to 55 mph.
Traffic Shift
Southbound traffic shifted onto the lanes constructed in the median of I-15 in May 2026. Watch the video to the right to see a visual of how traffic shifted.
Spring 2026 Update
It’s time for another I-15 construction update!
Check out the video to learn the latest about upcoming work on the I-15 Northgate to Blackfoot Widening and Riverton Road Bridge projects.
Construction on I-15
Crews began work to widen I-15 between the Northgate Parkway and Fort Hall interchanges (exits 73 & 80) in September 2024. Construction is anticipated to be completed in 2027.
ITD is widening I-15 to three lanes in each direction to improve safety, increase capacity and modernize aging infrastructure.
Improvements include:
- Improving bridges, overpasses and interchange structures.
- Widening I-15 to three lanes in each direction.
- Constructing a barrier wall in the median.
What’s happening now?
Crews have constructed the new lanes in the median, the median barrier wall and the northbound lanes on I-15. Southbound I-15 traffic is shifted into the new lanes in the median and crews are constructing the new southbound lanes of the interstate. Motorists can expect:
- Nighttime lane restrictions.
- Traffic shifts and lane changes.
- Reduced speed limits.
- Ramp work and changes at exits 73 and 80. Temporary ramps may be shorter than current ramps.
Frequently Asked Questions
The design of this project included completing an environmental evaluation, gathering traffic and geotechnical information, surveying, designing improvements, and gathering input from the public, Shoshone Bannock Tribes and local jurisdictions.
Construction includes widening I-15 to three lanes in each direction and replacing machine underpass bridges and the 2 1/2 Mile Road Bridge over I-15.
Most of I-15 was constructed in the 1960s and 1970s. With the increased population and travel across eastern Idaho, it is necessary to modernize aging infrastructure and increase capacity and safety to meet the region’s travel needs along the I-15 corridor.
Construction to widen the interstate between the Northgate Interchange and Fort Hall is expected to be completed in 2027.
The construction of improvements between the Fort Hall Interchange and Blackfoot is dependent on the availability of future funding sources.
Elements of this project are funded with Transportation Expansion and Congestion Mitigation (TECM) funds as part of the Leading Idaho TECM Program. The program allows ITD to accelerate project timelines to address rapid growth and build critical infrastructure today that would otherwise take many years to fund and build. For more information on TECM funding, visit itd.idaho.gov/funding.
Timeline
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2022-2024
Conduct environmental evaluation and develop design plans
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2024
Construction to widen I-15 between Northgate and Fort Hall begins
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2025
Construct the new lanes in the median of I-15 and the median wall
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2026
Construct the new northbound lanes of I-15
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2027
Construct the new southbound lanes of I-15
Stay in touch!
Sign up for text updates or text 15CONSTRUCTION to 1-866-483-8422.
Call (208) 252-5553
Email info@pocatellotoidahofalls.org
Check Idaho 511 for the latest traffic updates