Road work coming to two I-84 bridges near Boise. One is a critical commuter route
Closures and detours are coming to two bridges that run over Interstate 84 in the Treasure Valley, the Idaho Transportation Department announced Friday.
Road work will affect the I-184 Connector in Boise and the Karcher Interchange in Nampa — plus travel for the more than 130,000 vehicles that make trips along the Interstate between Boise and Nampa daily.
Starting Monday, Nov. 17, ITD will institute lane reductions on the Flying Wye Interchange for two weeks to treat its asphalt and repaint the road, according to a news release from the department. One lane will remain open throughout the $270,000 project, ITD spokesperson Jill Youmans told the Idaho Statesman by email.
The first phase will involve nightly lane reductions from 10 p.m. to 5 a.m. Crews will perform micro milling, a process that removes the top layer of pavement “to improve the surface texture ahead of winter,” Youmans said. Drivers can expect reduced speed limits during this phase, which is expected to last three days, according to an ITD Facebook post.
In a second phase, crews will repaint the interchange’s lanes — a process that must be done during the day when temperatures are warm enough for the paint to set properly, according to ITD.
The striping work will also take roughly two to three days, but the exact dates depend on contractor availability and weather, Youmans said. The hours and traffic configuration of the lane closures during striping have not yet been determined, she said.
The Flying Wye connects drivers exiting downtown Boise on the Connector to I-84, and vice versa. It’s one of the most congested roads in the Treasure Valley, with nearly 150,000 vehicles a day traveling the stretch between the Flying Wye and the Eagle Road Interchange.
More closures at Nampa I-84 interchange
Monday will also mark the start of the latest round of closures as ITD continues upgrading I-84’s Karcher Road Interchange in Nampa.
The Karcher overpass will close on Monday and Tuesday nights from 10 p.m. to 5 a.m., forcing detours for drivers traveling on Karcher Road, also known as Idaho 55.
The closures will allow ITD to remove “large steel structures” that now hold signs above the bridge, according to ITD. Those will be replaced with updated signs reflecting the bridge’s new lane configuration.
The new configuration includes the addition of a dedicated right-turn lane for traffic coming off I-84 and onto Karcher. It’s part of a two-year project to improve traffic flow and safety at the interchange, which has caused a series of closures since construction began in early 2024.
In the latest one, ITD instructs drivers to make the following detours.
Drivers traveling south on Karcher Road:
- Travel south on the Karcher Bypass.
- Turn right onto West Karcher Road.
- Turn left onto Midland Boulevard.
- Turn right onto Caldwell Boulevard.
- Continue straight to Karcher Road.
Drivers traveling north on Karcher Road:
- Use the eastbound on-ramp to merge on to Interstate 84.
- Exit I-84 at Northside Boulevard (Exit 35).
- Travel north on Northside Boulevard.
- Turn left onto Karcher Road/Karcher Bypass.
This story was originally published November 14, 2025 at 4:46 PM.
