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US 12 - Widening From SR 124 to Walla Walla


Winter 2015

  • Money for design is no longer available for phase 7 and WSDOT will continue when funding becomes available.
  • So far, crews have widened US 12 from the Snake River Bridge to Wallula and from Frenchtown to Walla Walla.

This multi-phase project consists of seven construction phases and a planning phase. The construction portion will widen the US 12 corridor to four lanes from the SR 124 junction to the Walla Walla River. The planning phase will determine the preferred alignment for Highway 12 from the Wallula Junction near the Walla Walla River to Walla Walla.

Why is WSDOT widening US 12?
Constructing a four lane divided highway will reduce congestion and intersection related accidents. The average daily traffic on this route ranges from 7,000 to 13,000 vehicles.  As many as 23 percent of the vehicles are heavy trucks. Over ten million tons of cargo travel this section of US 12 each year. Slow moving trucks and recreational vehicles impede the flow of traffic on this two-lane facility.

Our Partners
This project is the result of local agencies, businesses, and WSDOT coming together to address transportation issues related to the area. Each partner has provided financial and political support for a safer, less congested roadway that will enhance the economic vitality of the area.

The End Result
US 12 will be a four-lane divided highway for 40 miles from the junction of SR 124 to Walla Walla. Bridges will be widened and new bridges constructed to accommodate the new lanes. Intersections will be improved by the addition of right and left turn lanes. Currently there are two lanes; when these projects are completed, there will be four lanes.

Project Benefits

  • Safety. Providing a four-lane divided highway greatly enhances safety for this corridor. Traffic will be separated by a median or concrete barrier. Access to US 12 will be limited to channelized county road intersections.
  • Congestion Relief. WSDOT’s computer modeling estimates there will be at least one hour each day of heavily congested conditions between Tri-Cities and Wallula by the year 2020. By comparison, if the project were built, we would see zero hours a day of congestion through 2020. To learn more about WSDOT's congestion relief efforts visit the WSDOT Congestion Relief site.
  • Environment. WSDOT completed an environmental assessment for this corridor to identify the potential impacts to the natural and human communities. This project required careful attention to design as it passed through and affected several federally managed sensitive resource lands including: the McNary National Wildlife Refuge, the Two Rivers Peninsula Habitat Management Unit (HMU), the Wallula Habitat Management Unit, and the Madame Dorian Park. Several strong partnerships were developed with state and federal agencies in order to address the substantial environmental challenges of this corridor improvement project.

What is the project timeline?
SR 124 to McNary Pool
Construction began on this section in January 2005.  This section was complete and open to traffic in November 2005.
McNary Pool to Attalia
Construction began on this four mile section in May 2003.  This section was complete and open to traffic ahead of schedule in August 2004.
Attalia Vicinity
Construction on this phase was started in July of 2006 and completed in October 2007.
Wallula Junction to Walla Walla Corridor Study
This study to evaluate alternatives and determine the final location for continuing the four-lane alignment of US 12 from Wallula to Walla Walla was completed in June 2009.

Attalia Vicinity to US 730
WSDOT has identified a northerly corridor that eliminates the need for this Phase 5 widening project and will use the remaining Phase 5 funding to evaluate the ultimate connection between US 12 and US 730.

• Frenchtown Vicinity to Walla Walla
Construction started in March 2008 and completed summer 2010.

• SR 124 Burbank Interchange Improvements
Construction started March 2011 and completed June 2012.

Financial Information

This multi-phase project is funded through the following sources:

  • 2005 Transportation Partnership Package 
  • 2003 Nickel Funding Package
  • Existing Funds

The Washington State Legislature has made funding available over the next ten years to complete this twelve mile corridor improvement and develop a plan for the 30 miles from Wallula Junction to Walla Walla. 

How can I get more information?
Troy Suing
Assistant Regional Administrator for Planning and Programming
WSDOT South Central Project Office
2809 Rudkin Rd.
Union Gap, WA 98903

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