As identified in the graphic below, planned improvements are divided into different segments. Each segment has a unique schedule and they are not scheduled for construction in a consecutive, east-to-west or west-to-east sequence. Instead, segments will be constructed in order of most urgent need and available funds. All segments will widen the highway on the south side of the roadway from 2 to 4 lanes. During construction, work will occur day and night with traffic limited to one lane in each direction. The segments are as follows:
Chinden Boulevard, a section of U.S. 20/26, is one of the few east-west commuter routes that connects Boise to Interstate 84 in Caldwell. The majority of Chinden between I-84 and Eagle Road is a two-lane rural highway. As the land around the roadway develops, Chinden is becoming a busy urban corridor, particularly between Ten Mile Road and Eagle.
Large-scale commercial and residential developments are being planned at the southwest corner with Ten Mile and the southeast corner with Linder Road. With development expected to continue, the region is transforming from a historically agricultural area to an urban corridor.
From 2015-2017, ITD conducted an Environmental Assessment (EA) of the corridor to determine recommended roadway improvements and identify right-of-way needs through 2040. The National Environmental Policy Act (NEPA) process included an extensive public involvement effort featuring public open houses, property owner meetings, online public meetings and live online Q&A sessions. ITD also worked closely with its local government partners to identify needs and develop solutions that meet the future demands of this growing region in Ada and Canyon counties.
The resulting recommendation includes the following improvements by 2040:
Phase 1: Expand Chinden from 2 lanes to 4 lanes between Eagle and Star Road.
Phase 2: Projections suggest a long-term need for 6 lanes from Eagle to I-84, ultimately. ITD will construct additional lanes on the corridor based on then-current traffic and growth patterns.
Phase 3: Construct high-capacity intersections (CFI’s) at Eagle, Locust Grove Road, Meridian Road, Linder, and Middleton Road. In October 2017, the Federal Highway Administration (FHWA) approved the recommendations. Segments of Chinden between Eagle and Star were soon identified as having the most immediate needs due to increasing traffic volumes and impending development.
What is a CFI?
The EA identified the future need for high capacity intersections at Middleton Road, Linder Road, Meridian Road, Locust Grove Road, and Eagle Road. These Continuous Flow Intersections (CFI), example in the linked graphic below, can accommodate higher traffic volumes than a traditional intersection. Current traffic and near-term demands do not warrant CFI’s at this time. Planned improvements feature traditional intersections with the ability to expand to CFI’s when necessary.
View the CFI Diagram
National Environmental Policy Act
The National Environmental Policy Act (NEPA) is a procedural statute (40 CFR parts 1500 thru 1508) for decision-making during federal projects that assures proper analysis of social, economic and environmental impacts are performed and disclosed. Chinden work is federally funded through FHWA and as such is subject to federal regulation. ITD, in consultation with FHWA, followed the NEPA process to prepare a NEPA Document. The NEPA process studied a reasonable range of alternatives, considered appropriate mitigation for impacts, included interagency coordination and consultation, and provided the public an opportunity to participate in the process and comment. The studies, agency coordination, public participation process and comments are all summarized in the EA.
View the Environmental Assessment Document