The Scarsella Brothers are leading the $78 million reconstruction of Idaho I-90 interchange and local roads in Post Falls, improving safety and capacity. The complex project includes bridges, pedestrian structures, and upgraded intersections. Construction challenges and tight timelines are being overcome as work progresses towards completion in 2026.
Idaho Transportation Commission photo
The interchange at Interstate 90 and State Highway 41 in Post Falls, Idaho, is undergoing multiple improvements.
The Idaho Transportation Department (ITD) is reconstructing the interchange at Interstate 90 and State Highway 41 in Post Falls, as well as improving SH 41 and local roads surrounding the interchange.
The project was awarded to Scarsella Brothers Inc. of Seattle, Wash., for $78 million.
The current interchange was constructed in the early 1970s, with modifications to the eastbound off-ramp in the early 1990s.
"The irregular intersection of Seltice Way and ID 41 has served its design life and is now a challenge for motorists," said Heather McDaniel, public information officer of the Idaho Transportation Department, District 1. With average daily traffic numbers for 2025 around 66,250, she added, "Congestion in recent years has contributed to multiple severe and fatal crashes, especially at the westbound off-ramp."
Plans
The plan to replace and upgrade the interchange at I-90 and SH 41 emerged as part of the I-90 Corridor Study from the Washington state line to 15th Street in Coeur d'Alene, Idaho, McDaniel said.
The interchange is a central point of connection for other corridor projects planned to be built in future years, including expansion of the interstate to four lanes in each direction and the development of other improved interchange locations at U.S. 95 and Northwest Boulevard.
"Once finished, the reconstructed interchange will improve safety, increase capacity, provide better connectivity to SH-41 and position I-90 for future expansion," said Shannon Stein, ITD project manager.
This complex interchange construction project includes building significant infrastructure such as:
• 1.3 mi. of I-90 pavement reconstruction;
• SH 41 widening and pavement reconstruction from Seltice Way to 12th Avenue;
• .5 mi. of widening and pavement reconstruction of Seltice Way;
• six permanent bridges;
• two temporary bridges;
• eight retaining walls;
• two pedestrian underpasses;
• one pedestrian bridge;
• upgrades to intersections with three traffic signals;
• one pedestrian ("hawk") signal; and
• utilities, drainage and signage improvements throughout the project limits
Funding
The ITD approved a bond sale in February 2022 to advance the project, enabling it to start construction one year early.
Funding for some elements of the project comes from Gov. Brad Little's "Leading Idaho" Initiative, which includes the "Transportation Expansion and Congestion Mitigation, or TECM, program. It is the largest transportation funding package in Idaho's history.
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. Because of the program, construction of the I-90, SH 14 interchange was advanced a full year earlier than expected.
According to Randy Durland, ITD's project manager, liquidated damages for not completing within 540 working days will be assessed at $12,000 per day. Conversely, there is a $300,000 incentive if both the following conditions are met:
• Complete Seltice Way construction so that lane reductions are in place less than a total of 200 calendar days.
• Sequence the work so that two through-lanes in each direction are open to traffic during peak travel hours on Seltice Way throughout the Ramp CD (westbound off) closure.
Progress
Construction will be under way through the summer of 2025. Work this year will include:
• building the new westbound off-ramp;
• building the new SPUI operation;
• widening SH-41 to Mullan Avenue; and
• finishing the SH 41/Mullan Avenue intersection.
The project will take four seasons to complete because ITD believes it's important to keep this interchange open to traffic during construction. If the interchange could be completely closed, construction could be completed more quickly.
Idaho Transportation Commission photo
This season will focus on constructing the concrete pavement of the SPUI as well as the signal structure for it, Durland said. To complete this work, crews are using a Guntert & Zimmerman S605 Slipform Concrete paver.
Interstate Concrete and Asphalt in Rathdrum, Idaho, is pouring the Hot Mix Asphalt (HMA) and concrete pavement surfaces. Any milled HMA removed from the existing pavement is being reused in a portion of the new pavement.
Scarsella averages 15 to 25 crew members onsite daily, working 7 a.m. to 5 p.m. Monday through Friday. Night work will be scheduled from 8 p.m. to 5 a.m. During special events, night work will begin at 10 p.m.
Noise, Safety Concerns
Based on the analysis, noise walls were not warranted; however, a study is underway to look at the expansion of I-90 and determine if they are warranted in the corridor.
The design team consulted with community partners such as emergency services and law enforcement to mitigate safety concerns with the construction of pedestrian underpasses. These underpasses will be well-lit and short enough to see through to maximize visibility and safety.
Idaho Transportation Commission photo
Both underpasses will be 14 ft. wide and 10 ft. tall, making them larger than the underpass to access Silverwood off U.S. 95. The inside of the underpass under the I-90 westbound on-ramp will be visible from Seltice Way, and the underpass under SH41 will be visible from Primrose Lane, which will improve safety and ease of patrolling.
Challenges
"Congested, staged construction has been the most challenging aspect of the project," Durland said.
Scarsella mitigated this challenge with scheduled night shift operations to complete complicated staged construction that would not be possible during the day with the amount of traffic within the project limits.
The speed limit was lowered to 55 mph on I-90 and 25 mph on SH 41 and Seltice Way. There are lane restrictions on SH 41, along with intermittent lane restrictions on I-90 at night.
The weather has played a major challenge when scheduling traffic switches on I-90. Cooler temperatures at night and abnormal popup storms have impacted many scheduled traffic switches that require careful planning with subcontractors to complete the work alongside Scarsella. Durland said that Scarsella and the subcontractors stayed focused on the goal and grouped other work that is not weather-dependent.
"ITD and Scarsella have been working closely together to deliver and complete this major intersection upgrade for local traffic," Durland said. Challenges with time constraints, traffic and staging have been a common topic of conversation.
Over the next four seasons, work will shift from I-90 to SH 41 and then to Seltice Way.
Project completion is expected in 2026. CEG
Lori Lovely
Lori Lovely is an award-winning journalist, editor and author of the children's book Isadora's Dance. She has worked for newspapers, magazines and niche publications, covering a wide-ranging list of topics that includes motor sports, construction, MSW, energy, environmental issues, water, animal rights and issues, history, Native American issues and people, real estate and home decor, farming and more. Her degrees in History taught this dedicated professional to research thoroughly and ask detailed questions in order to winnow interesting facts that convey the essence of the story. As a seasoned writer and compassionate storyteller, she accurately portrays the subject in a manner that entrances the reader.
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