Construction to start Monday on the I-84, Karcher Interchange in Nampa

Posted on by Sophia Miraglio
I-84 looking west towards exit 33 in Nampa

The Idaho Transportation Department (ITD) is beginning construction on the I-84, Karcher Interchange in Nampa on Monday as part of the Leading Idaho program. Improvements will increase safety and mobility at the interchange and along State Highway 55 (SH-55)/ Karcher Road between the westbound ramps and Sundance Road. Construction is expected to be complete in fall 2025.

Motorists will see overnight lane closures on I-84 starting Monday, Feb. 19. Crews will shift traffic to create a work zone and begin building the third lane on the overpass bridge.

During the project, motorists can expect:

  • All lanes open during the day.
  • I-84 overnight closures for traffic shifts, bridge work and girder placement.
  • Major work will take place at night from 10 p.m. to 5 a.m. with one lane open in each direction on Karcher Road.
  • Bike lanes and sidewalks in the project area will be detoured.
  • Access to local businesses will be open.
  • Speed limits will be reduced.

 

“The Karcher Interchange’s design life has been outpaced by the huge amounts of growth Nampa has seen recently,” Resident Engineer Andrew Linder said. “The work on the interchange will account for this growth by adding capacity and improving safety. ITD is making every effort to minimize impacts to businesses in the area and the traveling public.”

Improvements will include:

  • Reconfiguring westbound and eastbound off-ramps to improve safety and traffic flow, and increase capacity.
  • Widening the interchange bridge to provide a dedicated lane for the westbound off-ramp traffic to travel westbound on Karcher Road (SH-55).
  • Adjusting signals at ramp intersections, Caldwell Blvd and Cassia St.
  • Adding a third westbound lane and dedicated right turn lane at the intersection of Karcher Road (SH-55) and Caldwell Boulevard.
  • Adding a pedestrian flashing beacon at the I-84 eastbound on-ramp and widening some sidewalks within project limits.
  • Repaving Karcher Road (SH-55) from the westbound on-ramps to Middleton Road.

This project is funded with Transportation Expansion and Congestion Mitigation (TECM) funds as a part of Governor Little’s Leading Idaho TECM program. This initiative allows ITD to address rapid growth and aging infrastructure in critical corridors throughout the state.

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