Overview
The Chinden West corridor is a vital east-west route linking Boise and Caldwell, serving as a key connector between I-84 and Eagle Road (SH-55). This heavily traveled section of U.S. 20/26 plays a critical role in regional mobility. In response to increasing traffic demands and projected growth in the Treasure Valley, the Idaho Transportation Department has studied travel along Chinden Boulevard and developed a comprehensive plan that will improve safety, reduce congestion, and increase capacity.
Background
ITD completed an Environmental Assessment in 2017 that described that U.S. Highway 20/26 (Chinden Boulevard) needed to be widened to a four-lane highway by 2032 and to six lanes by 2040 to meet future travel demands. The corridor expansion plan includes two phases of development:
- Interim Improvements: Phase 1 (widening the highway to four lanes)
- Future improvements: Phase 2 (widening the highway to six lanes)
Middleton Road to Star Road
ITD looks forward to construction of the last interim section from Middleton Road to Star Road. The Middleton Road to Star Road project will widen the highway from two to four lanes and improve intersections to enhance capacity and mobility for nearby residents, businesses, commuters and freight haulers.
The final design for this section is complete, and right of way acquisition is ongoing. A noise study completed for this section is currently in review.
Construction is currently anticipated for 2029. ITD will look for opportunities to accelerate construction, including using savings from other projects, grants or new revenue from the Idaho Legislature or Congress.
Phase 1: interim widening from I-84 to Eagle Road (SH-55)
In order to widen this entire corridor quickly, ITD has executed these improvements as separate projects, prioritizing areas based on urgency and available funding. Safety upgrades include improved shoulders, signalized intersections, and a separated shared-use path for cyclists and pedestrians.
Future improvements: Phases 2 and 3
Projections suggest a long-term need for six lanes between I-84 and Eagle Road (three in each direction). Phase 2 will widen the highway to six lanes. ITD will construct additional lanes based on traffic demand and funding availability. Funding has not been identified for future improvements.
Timeline
Construction has been underway at various sections of the corridor since 2020.
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2020
Locust Grove to Eagle Road completed
- Widened from two lanes to four lanes with a center turn lane
- Built 10-foot detached shared-use paths for pedestrians and cyclists
State Highway 16 to Linder Road completed
- Widened from two lanes to four lanes with a center turn lane
- Built 10-foot detached shared-use paths for pedestrians and cyclists
- Improved intersections with signals and turn lanes
- Funded the roadway improvements through the STAR agreement, with Costco paying for the road improvements and being reimbursed through sales tax revenue generated by the development.
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2021
Linder Road to Meridian Road completed
- Widened from two lanes to four travel lanes with a center turn lane
- Funded the project through the STAR agreement, with Linder Village paying for the project and being reimbursed through sales tax revenue generated by the development
Meridian Road to Locust Grove completed
- Widened to from two lanes to four travel lanes with a center turn lane
- Built 10-foot detached shared-use paths for pedestrians and cyclists
- Funded the project through the STAR agreement, with Linder Village paying for the project and being reimbursed through sales tax revenue generated by the development
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2024
Star Road to State Highway 16 completed
- Widened Chinden Boulevard from two lanes to four travel lanes with a center turn lane
- Built 10-foot detached shared-use paths for pedestrians and cyclists
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2025
I-84 to Middleton Road completed
- Widened Chinden Boulevard from four lanes to six lanes
- Constructed a raised island median to separate eastbound and westbound traffic
- Improved roadway shoulders
- Built 10-foot detached shared-use paths for pedestrians and cyclists
- Added signalized intersections
- Constructed new canal bridges
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2029
Construction planned for Middleton to Star Road
Chonne Sherman
Project Inquires
Environmental documentation
Resources
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2019 video explaining the vision for the corridor