US 12 - Anderson Rd to Moon Rd - Safety Improvement

Project news

  • After considering traffic needs and the community’s views, WSDOT has chosen to build roundabouts at the intersections of Anderson Road and Mood Road SW.
  • Learn more about roundabouts and how they work.

Why is WSDOT planning changes to the US 12 intersections of Anderson and Moon Roads?
Safety is WSDOT’s number one priority. Both intersections were identified as locations that have a history of collisions.

WSDOT explored alternatives to help reduce the potential for collisions at both intersections. After thorough review and analysis that incorporated public input, WSDOT will build two single-lane modern roundabouts at each intersection. Modern roundabouts provide a cost-effective and efficient solution to keep traffic moving while reducing the likelihood and severity of collisions.

Anderson Road
Anderson Road south of US 12 is the main entrance for visitors and freight traveling to and from properties owned and operated by the Confederated Tribes of the Chehalis Reservation. WSDOT is proposing to construct a three-leg modern roundabout at this location. This roundabout will be large enough to accommodate emergency vehicles, farming equipment, log trucks and other semi-trucks with trailers.

This proposal will permanently close access to Anderson Road north of US 12. Drivers who use that roadway will be able to reach US 12 via Sickman-Ford or Moon Road Southwest. Anderson Road south of US 12 will remain open.

Moon Road
Moon Road south of US 12 is primarily intended for residents. WSDOT is proposing to construct a modified four-leg modern roundabout at the intersection. The modified roundabout is intended to assist local traffic while directing regional traffic to Anderson Road. This will be accomplished by reducing Moon Road south of US 12 to one northbound lane, which will prohibit US 12 traffic from turning onto southbound Moon Road. This provides greater access to US 12 for residents living south of the highway than a closed median intersection would have provided. A closed median had been initially considered by WSDOT, but this concept was developed after taking feedback from the public. This method also preserves full access for drivers who travel to Moon Road north of US 12, something many in the community requested during the WSDOT open house held during summer 2016.

Why roundabouts?
WSDOT has been using roundabouts on Washington highways since 1997. Roundabouts at these locations offer the greatest safety benefit by reducing the potential for severe collisions, while improving connectivity and economic development opportunities along the corridor.

Roundabout Benefits
Studies have shown roundabouts in certain instances have the potential to reduce the number of collisions when compared to stop signs or traffic signals.

Studies by the Federal Highway Administration have found roundabouts can increase traffic capacity up to 50-percent compared to traditional intersections.

Roundabouts also help save limited state resources since they do not require ongoing maintenance such as the work required for traffic signals.

The End Result
Crews will build modern single-lane roundabouts at the intersections of Anderson and Moon Roads. Both roundabouts will enhance mobility and travel through the area. They are designed to accommodate large trucks traveling to and from nearby industrial and distribution businesses.

Project Benefits

• Improved traffic flow – Roundabouts are designed to promote a continuous, circular flow of traffic.
• Saves money – Reduced maintenance and repair costs.
• Accommodates all vehicles - Including farm, freight, and log trucks
• Provides access for pedestrians and bicyclists

What is the project timeline?

  • Aug. 2016 - WSDOT open house
  • Winter 2018 - Project advertised for competitive bidding
  • Spring/summer 2019 - Construction occurs
  • Fall 2019 - Project complete


Financial Data for PIN 301201G
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $3,018
CWA $0
Total $3,018


How can I get more information?

John Romero
WSDOT Project Engineer

Doug Adamson
WSDOT Communications