Idaho Transportation Department

U.S. 20/26 Corridor Preservation Study, Caldwell to Boise

An aerial view of U.S. 20/26 looking west from Eagle Road

Study Facts

Key Number: 7826
Project No.: STP3230(106)

The U.S. 20/26 Corridor Preservation Study team will conduct planning, engineering design, and environmental review necessary to produce a corridor plan, right-of-way plans, and an environmental assessment based on the increased traffic volume on the corridor. The study area is between I-84 in Caldwell and Eagle Road.

Planning

Transportation planning is an important component of this study. It allows ITD and COMPASS to:

Develop safety and congestion management strategies in the corridor area, including limiting access to the highway
Identify opportunities to accommodate alternative transportation modes, such as transit, cycling and walking
Identify strategies to preserve right-of-way
Prioritize proposed improvements
Assure consistency between the corridor plan and the land use comprehensive plans for the cities and counties

Engineering Design

Engineers are designing what 20/26 will look like in the future. They are proposing a variety of typical sections. A typical section is a cross section of the highway. It shows:

Number of lanes
Shoulder width
Medians
Roadside features, such as curb, gutter, sidewalks, pathways, landscaping and lighting

The engineers will determine the costs and property impacts of the various alternatives.

Environmental Review

The National Environmental Policy Act (NEPA) requires that an environmental review be completed before right-of-way can be acquired with federal funds. The U.S. 20/26 Corridor Preservation Study will result in an environmental review that identifies impacts to:

Local land use
Community facilities and businesses
Cultural and historical resources
Noise and air quality
The natural environment

The engineers will determine the costs and property impacts of the various alternatives.

Study Description

Several key documents will be completed during this study, including:

A corridor plan that identifies future right-of-way needs and proposed lane configurations. A corridor plan is a series of recommendations for managing and improving the transportation system within a specific corridor, based on a 20-year forecast.
An approved environmental document that will evaluate possible impacts to: agricultural resources, air quality, native plants and animals, cultural and historical resources, geology and soils, hazardous and toxic materials, hydrology and water quality, land use planning, noise, mineral resources, and recreation.
An access management plan. Access management describes a set of design techniques that state and local governments use to control access to highways, major arterials and other roadways.

Study Background

U.S. 20/26 is one of the few east-west roadways in the Treasure Valley that runs from Caldwell to Boise. It is currently a two-lane rural roadway with a 55 mph speed limit.

The land use along the roadway is mainly agricultural; however, an increasing number of residential subdivisions are being constructed. Right-of-way costs along U.S. 20/26 are escalating. The future is expected to bring mixed-use development that will transform U.S. 20/26 into an urban corridor.

Boise, Caldwell, Eagle, Meridian, Nampa, Star, Ada and Canyon counties, Canyon Highway District No. 4, Ada County Highway District, COMPASS Board and ITD are all involved with this study and will be asked to adopt the final plan.

Study Update

Based on input and analysis throughout the project, the study team has narrowed the options down to one build alternative and a “no-build” option for consideration. The preferred alternative would widen the highway to 4 lanes from Aviation Way to McDermott Road and to 6 lanes from McDermott Road to Eagle Road lanes, and the “no-build” option would leave U.S. 20/26 in its current condition. The National Environmental Policy Act (NEPA) requires that the “no-build” option be considered.

This build option is consistent with comments ITD has heard from the public, elected officials, agencies and city planners throughout the study process. Transportation agencies and city planners will continue to coordinate on issues such as access management and future development as the study progresses.

Click here for what we learned at the last public meeting.

Make Comments

The Idaho Transportation Department values your input. Submit written comments using one of the forms below or contact for more information.
•Email Us please include your name and address
•Download a comment form (word doc)

Contacts

Aaron Bauges
aaron.bauges@itd.idaho.gov
(208) 334-8964

Don Matson, COMPASS Principal Planner and Project Manager
dmatson@compassidaho.org
(208) 855-2558 ext. 230

Compliance with Title VI of the Civil Rights Act

The Idaho Transportation Department (ITD) is committed to compliance with Title VI of the Civil Rights Act of 1964 and all related regulations and directives. ITD assures that no person shall on the grounds of race, color, national origin, gender, age, or disability be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any ITD service, program, or activity. The department also assures that every effort will be made to prevent discrimination through the impacts of its programs, policies, and activities on minority and low-income populations. In addition, the department will take reasonable steps to provide meaningful access to services for persons with Limited English Proficiency.