US-20 traffic to shift as South St. Anthony Interchange nears completion

Road construction with closures and traffic shift on US-20 South St. Anthony interchange.

Beginning early this week, traffic on U.S. Highway 20 will be routed onto the newly built overpass bridge at South St. Anthony Exit 344. This marks the final stages of construction on a new full interchange at this location.

North and southbound motorists were previously routed onto the ramps while the overpass bridge was being constructed, with speed limits lowered to 35 mph. Traffic will now move to travel on mainline US-20 at a reduced work zone speed.

With this traffic shift, South St. Anthony ramps will be closed as work continues on 400 North under US-20. Workers and equipment will still be present on site, so drivers are urged to stay aware and be cautious.

This project is expected to be substantially complete later this summer, with the ramps and turning movements onto 400 North open then.

Funding for this project is assisted by Governor Little’s Leading Idaho Transportation Expansion and Congestion Mitigation (TECM) fund. The Leading Idaho initiative allows ITD to take a deliberate approach to invest in projects in corridors that will enhance safety, improve mobility, further strengthen Idaho’s economy, and positively impact communities across the state for years to come.

Updates on this project and others across Idaho can always be seen on the Idaho 511 app, or at 511.idaho.gov.

Expect lane closures and delays during unique inlaid striping operations on Idaho Falls roads and others

Road of SH-33 in Idaho, showing a notch ground into the pavement where paint will be applied and a truck in the background.

Traffic will be affected as the Idaho Transportation Department and contractor partners conduct inlaid striping operations on State Highway 33, U.S. Highway 20, and Interstate 15 Business Loop over the next two weeks.

Beginning today, lane closures will be in effect where work is currently underway on SH-33 between Sage Junction and Rexburg. Four miles at one time will be reduced to one lane, with flaggers and pilot cars directing traffic through the work area. Motorists should watch for reduced speed, large equipment and signs indicating construction ahead.

Roadways will be worked on in this order, with all operations expected to be completed by August 15:

SH-33 between Sage Junction and Rexburg, milepost 59 to 78.

US-20 west of Idaho Falls, milepost 301 to 307, beginning next week.

I-15 Business Loop in Idaho Falls (Sunnyside Road from I-15 to Yellowstone Road).

I-15 Business Loop in Idaho Falls (Yellowstone Road from Sunnyside to Broadway).

Operations on SH-33 and US-20 are being conducted during daytime hours. Crews will work through the night on the I-15 Business Loop in Idaho Falls.

A pilot car and flaggers will only be present on SH-33 this week. Traffic will be directed into one lane and continue to move around the work area on US-20 and I-15 Business Loop.

Inlaid striping is relatively unique in Idaho. The operation involves grinding into the pavement very slightly, creating recessed notches that paint is then applied within. This method aims to extend the life and reflectivity of pavement markings.

Updates regarding these efforts and all roadwork in Idaho can always be found on the Idaho 511 app, or at 511.idaho.gov.

Historic System Interchange rebuild nearing successful completion

Aerial view of the system interchange at Pocatello.

With the painting of final lane markers on the new roadway, construction at the I-86/I-15 “Flying-Y” System Interchange in Pocatello is coming to a successful conclusion. Begun in July 2022, the three-year $112 million project has dramatically changed the drivability of the interchange.

“We spent over eight years from design to actual construction of the project. We’re pretty proud of it. It’s one of the bigger projects we’ve designed. It’s one of the largest projects ever designed entirely by ITD staff and inspected with ITD personnel. Most of the people on the team live here locally and this has been a really meaningful project for us to make sure we did our very best,” said Project Engineer Aaron Baird.

Critical areas that were improved include the northbound Pocatello Creek on-ramp, the northbound-to-westbound collector distributor, and the eastbound-to-northbound ramp. Each of those improvements made merging from one Interstate to the other smoother and safer for motorists.

“We’re excited for people to use the final product. We hope it’s something that will last a long time and keep the travelling public safe as they use it,” said Project Manager Greg Roberts.

The scale of the endeavor has been truly historic. Approximately 1 million cubic yards of excavation have been completed. In addition, about 490,000 tons of base material was brought in; 116,000 tons of asphalt were placed; and over 7,700 cubic yards of concrete were poured. Nearly 70,000 square feet of retaining walls were also built throughout the project area. Finally, ITD built eight new bridges. Four of those have precast concrete girders and four have steel girders. In all, over 5 million pounds of steel has been used in the new bridges.

Construction crews worked year-round and around the clock for approximately three years to complete the project. To minimize disruption to traffic, key demolition operations were conducted at night. These efforts minimized the impact on traffic while the interchange was being reconstructed.

In addition to the major changes inside the Flying-Y design, the Chubbuck Road overpass was reconstructed as an underpass to improve site distances and vertical clearance on I-15, and to improve access to the Wellness Center from Chubbuck. The new underpass is significantly wider and includes bike lanes and sidewalks.

ITD also worked closely with the Portneuf Greenway to construct a pedestrian and bicycle path on the east side of the worksite to connect the Greenway to the Wellness Center.

Work left to wrap up the project will be off the roadway and conducted on the shoulders. In addition, ITD will be seeding open ground with native grasses.

“Thank you for being patient with us and seeing our vision, seeing what we’re trying to do to positively impact this community,” said Project Manager Zak Johnson.

District Engineer Todd Hubbard echoed those sentiments, “This project has been a great success and is an important addition to the community for the safety of drivers. It has been a lot of work to get all of it completed and to keep traffic moving. I want to thank everyone for their patience as we have worked on this project over the last three years. And a thank you to the project team and Sundt-Cannon Joint Venture for a project well done.”

Drivers are encouraged to remain attentive, move over for workers and emergency vehicles, and follow posted speed limits.

Chubbuck Road to open for Fourth of July weekend

Chubbuck road underpass as viewed from the west.

Chubbuck Road is open for traffic under Interstate 15. As part of the redesign of the System Interchange project Chubbuck Road was rebuilt as an underpass with lanes for bicycles and sidewalks. Over the last month the new underpass was closed so crews could build the eastbound lane, construct sidewalks, paint permanent lines and add signs.

ITD expects no further closures of Chubbuck Road. However, crews will continue to work around the site adding vegetation and doing cleanup work. Drivers are encouraged to slow down for workers on and near the roadway.

No cleanup work will occur during the holiday.

Originally built in the 1960s, the I-86 and I-15 System Interchange is undergoing a rebuild to improve safety and replace aging infrastructure. This week crews are painting the final lane lines throughout the project area. Once the lines are completed the remainder of the project will consist of seeding vegetation and other cleanup work that will not affect traffic.

Motorists are encouraged to use 511.idaho.gov or the 511 app to keep track of project detours. Project details are available on ITD’s projects website at itdprojects.idaho.gov/i-86i-15-system-interchange.

Chip sealing to begin Wednesday at I-86 and I-15 System Interchange

Aerial photo of the system interchange at Pocatello.

Beginning tomorrow the Idaho Transportation Department will chip seal the System Interchange in Pocatello. Once this work is complete, the roadway will be restriped to indicate the final lane configurations.

Chip sealing covers temporary lane markings used throughout various phases of construction and maximizes the taxpayers’ investment by extending the lifespan of the pavement. A sticky slurry is sprayed on the pavement then rock chips are applied on top for a long-lasting seal. This treatment protects pavement from sun, oxidation, weather, water, oil and gas, and increases traction for safety.

Tabs will be placed on the new chip seal to indicate lanes for the short time before striping work can occur.

The previous connection between I-86 and I-15 was originally built in the 1960s. Now nearing completion, the System Interchange is a $112 million redesign to improve safety and replace aging infrastructure that began construction in 2022.

Motorists should carefully follow signs and slow down to posted speed limits while traveling through the construction area. With crews working day and night at the System Interchange, it is especially important that drivers be alert and travel safely.

Motorists are encouraged to use 511.idaho.gov or the 511 app to keep track of related detours. Project details are available on ITD’s website at itdprojects.idaho.gov/i-86i-15-system-interchange.

Inkom on-ramp to northbound I-15 (Exit 58) night closures planned for next week

Map of detour in construction area around Inkom.

Due to bridge demolition, the Inkom northbound entrance ramp onto I-15 will be closed for two nights. The West Inkom Interchange northbound entrance ramp (Exit 58) closure will take place from 9 p.m. to 6 a.m. on Monday, June 23 and Tuesday, June 24, weather and other factors permitting.

Traffic will be detoured to Old Highway 91 and then to Exit 63 to head north on I-15. Please watch for crews, use caution, and drive safely.

Due to the nature of the work, considerable noise is expected during the bridge demolition.

The Idaho Transportation Department is in the process of replacing bridges on I-15 at Inkom:

Over the Union Pacific Railroad tracks and Old Highway 91.
Over Rapid Creek Road (Main Street).
I-15 bridges and reconstructing the West Interchange.

ITD combined and streamlined the projects to reduce the construction timeline to approximately two years rather than doing one location at a time over three years. This approach minimizes disruption to the local community and the traveling public and efficiently uses construction funds.

To learn more about the project or sign up for construction updates, please visit: itdprojects.idaho.gov/pages/i15-inkom-corridor. This temporary closure and other traffic impacts will be posted to 511.idaho.gov.

Paving begins north of Blackfoot

A dump truck and paver working on repaving a road.

Tomorrow the Idaho Transportation Department will begin repaving the southbound lanes of Interstate 15 from the Rose/Firth Exit 98 to one mile north of West Blackfoot Exit 93. Traffic will be reduced to one lane in each direction and moved over to the northbound side of I-15.

The project will reconstruct the road to address rutting and potholes. Work is anticipated to be completed in mid-August. The northbound lanes were similarly repaved last year.

Motorists should carefully follow signs and posted speed limits while traveling through the construction area and are encouraged to use 511.idaho.gov or the 511 app to keep track of project detours.

I-84 will close Tuesday and Wednesday nights at the Karcher Interchange

Aerial photo of I-84 Karcher interchange near Nampa, Idaho.

The Idaho Transportation Department will close I-84 under the Karcher Interchange Tuesday and Wednesday nights to place girders on the overpass bridge. Detours will be in place.

Closures will run from 10 p.m. to 5 a.m. each night. On Tuesday night, westbound traffic will be affected, and on Wednesday night, eastbound traffic will be affected.

Motorists traveling westbound on I-84 Tuesday night will:

Exit I-84 at the Northside Interchange (Exit 35).
Travel north on Northside Blvd.
Turn left on to Karcher Road.
Travel west until you reaching the Karcher Interchange westbound on-ramp.
Use the Karcher Interchange westbound on-ramp to merge back on to westbound I-84.

Motorists traveling eastbound on I-84 Wednesday night will:

Exit I-84 using the Karcher Interchange eastbound off-ramp (Exit 33).
Cross Karcher Road.
Use the eastbound on-ramp to merge back onto I-84.

View the detour maps at ITDProjects.idaho.gov/pages/Karcher IC Maps

The girders were fabricated locally and will support the new westbound lane on Karcher Road over the interstate. ITD will host a Facebook live event during the girder placement on Tuesday, June 10. To tune in visit the ITD Facebook page.

Improvements on this project include:

Adding a free running right hand turn at the westbound off-ramp
Paving a third westbound lane on Karcher Road from the westbound off-ramp to Sundance Road
Reinforcing the Karcher Interchange and Indian Creek bridges to support the new lane
Updating signal equipment and adding a pedestrian flashing beacon at the eastbound on-ramp
Building a separated mixed-use path on the north side of Karcher Road

These improvements will increase safety and traffic flow at the interchange. Construction is expected to finish in fall 2025.

Stay informed by signing up for email and text alerts regarding project updates. Text 84CORRIDOR to 1-866-483-8422 or visit itdprojects.idaho.gov/pages/karcheric. For questions, contact the project team at (208) 334-8002. Maps and other details can also be found on the project website.

Construction to begin Monday in American Falls

Map showing final configuration of the intersection of Pocatello Avenue and SH-39

The Idaho Transportation Department will begin construction Monday at the intersection of Pocatello Avenue and State Highway 39 in American Falls. The $3.5 million project will redesign the busy intersection to improve safety.

Work will place a signal at the intersection Pocatello Avenue and SH-39. SH-39 will also be widened to four lanes from the intersection to Fairgrounds Road. New turn lanes will also be built on SH-39 for traffic heading to Pocatello Avenue.

This year construction will take place through August and will focus on realigning and widening the intersection. All lanes will remain open, but traffic will be slowed in the construction zone. Flaggers will be present during different phases of the project. Access to the American Falls Airport and the Power County Fairgrounds will remain open throughout construction.

In the spring of 2026 ITD will return to install the traffic signal. Project details are available on ITD’s projects website at itdprojects.idaho.gov/pages/pocatelloave-i86b.

Night work Tuesday and Wednesday on I-15 at 2.5 Mile Road

The Idaho Transportation Department will move Interstate 15 traffic Tuesday and Wednesday nights to accommodate girder placement at 2.5 Mile Road Bridge.

Traffic will be reduced to a single lane in each direction and shifted onto the same side of the interstate. Work will be conducted between 7 p.m. and 5 a.m. each night with a speed limit of 55 miles per hour through the work zone.

Motorists should carefully follow signs and posted speed limits while traveling through the construction area. With crews working day and night on the project to make I-15 three lanes from Northgate to Fort Hall it is especially important that drivers be alert and travel safely.

I-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.