The Idaho Transportation Department is constructing improvements to Interstate 84 between Franklin Road (Exit 29) in Caldwell and Karcher Road (Exit 33) in Nampa.
The work is expected to improve mobility, increase safety and benefit the regional economy for many years.
ITD is using variable speed limits within the Interstate 84 construction zone in Canyon County in order to improve mobility and preserve safety throughout the project’s lifespan.
The variable speed limits will allow for responsive adjustment to speed as activities within the work zone allow. When construction crews are not in the work zone or when safety barricades are in place, the speed limits can be raised from 55 mph to 65 mph. This further promotes mobility without sacrificing safety on the Interstate.
A flashing beacon will notify drivers in advance when speed limits are reduced from 65 mph.
As part of the project to improve I-84 between Caldwell and Nampa, the Idaho Transportation Department is replacing the Linden Street interstate bridge. Construction has required the Linden Street underpass to closed. The closure began in July 2021 and a detour is in place.
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Construction is underway on I-84 between Franklin Road (Exit 29) in Caldwell and Karcher Road (Exit 33) in Nampa. ITD will add a third lane in both directions and replace 20 bridges and other structures.
What’s happening now:
Please drive carefully.
This project is necessary to improve safety and mobility on I-84 in Canyon County. The existing interstate can no longer accommodate current traffic volumes at peak periods of the day. As the Treasure Valley continues to grow, congestion in this corridor will increase.
Improvements include:
ITD conducted a detailed traffic analysis of I-84 in 2018. ITD analyzed whether or not a new interchange would be needed along I-84 between Nampa and Caldwell. The analysis concluded widening I-84 and improving interchanges at Karcher/Midland (in Nampa) and Franklin Road (in Caldwell) will serve the needs of traffic beyond the design year 2045.
ITD made the difficult decision to close both Linden and Ustick this year in order to keep the I-84 project on schedule. This section of I-84 includes 20 bridges and other structures (canal crossings, culverts, etc.) that must be reconstructed to accommodate a third interstate lane. Many of these must be reconstructed at the same time.
In the case of the Linden underpass, the work zone is too tight to safely accommodate daily traffic volumes. However, emergency access will be available for police, fire and paramedics. Later in the project, ITD plans to open Linden Street to local traffic during the day. We regret the inconvenience to local travelers and look forward to the project completion. We appreciate your patience.
ITD’s detailed traffic analysis determined that three lanes on I-84 have shown to adequately serve the traffic needs in this area until 2045.
Once there is a need to expand, further widening will be possible. The current planned improvements will be built with space on either side of I-84 in Caldwell to add a fourth lane when necessary.
Yes, two emergency crossovers will be included in the I-84 Caldwell to Nampa project. Additional crossovers are not possible due to significant grade differences between the eastbound and westbound lanes of I-84.
Work between Karcher/Midland Boulevard and Franklin Road (Exit 29) in Caldwell began in Summer 2021 and is expected to be complete by summer 2023.
Crews cannot work 24 hour shifts due to lack of availability, as well as the significant cost for overtime. In addition, around-the-clock construction would create additional noise near residential areas of the project.
To learn more:
Visit the project website at ITDPROJECTS.ORG/84CORRIDOR
Text 84Corridor to 1-866-ITD-84CC
Call 208-334-8002
Email 84CORRIDOR@ITD.IDAHO.GOV
For business resources: ITDPROJECTS.ORG/I84Businessresources
The current closure will last until early 2022. Linden Street will close again in Spring 2022 to allow crews to complete work on the underpass bridge. All work on the bridge is expected to wrap up in Fall 2022.
There will be no access for motorists. The underpass is 24 feet wide and vehicle access would severely limit the amount of space for construction crews and equipment. Access will be maintained for emergency responders.
Linden Street is under the jurisdiction of the City of Caldwell. It will not be widened as part of the project to widen I-84.
At least one lane of I-84 will be open during construction at the Linden Bridge underpass. All lanes will be open during the day.
The detour route will take approximately 15 minutes.
New digital speed limit signs will be installed throughout the I-84 construction zone in Canyon County (about 6 miles). These signs will allow ITD to adjust the speed limit as needed, based on the level of activity in the work zone.
The regularly posted work zone speed limit will continue to be 55 mph. In areas where crews are not working near traffic, the speed limit will be raised to 65 mph. On rare occasions, the speed will be lowered to 45 mph.
ITD will place signs between Karcher Road (exit 33) and Franklin Road (exit 29) interchanges on:
The new signs will be installed in August 2021 and will be in place until construction is completed in 2023.
Variable speed limits have been tested in many other states. Past studies have shown that variable speeds:
ITD will coordinate with the contractors and crews each week to determine speed limits.
The speed may vary from one part of the work zone to the next. This area of I-84 between Karcher Road and Franklin Road includes several different projects and contractors.
A flashing beacon will notify drivers when speed limits have been lowered ahead of time.
For some major work zones in the past, ITD has lowered the speed limit, when crews were likely to be working. This is the first time ITD has implemented a variable speed limit work zone through this corridor.
