US 12 - Anderson Rd - Safety Improvement

Project news

  • After two months of work, crews are wrapping up construction on the new roundabout between Rochester and Oakville.
  • ​While crews will finalize work activities, the single-lane modern roundabout is open to travelers.
  • ​​Get email updates for this project and other major roadwork on state highways in Thurston County. 

Why did WSDOT build a roundabout at the intersection of US 12 and Anderson Road?
WSDOT explored alternatives to help reduce the potential for collisions. After thorough review and analysis that incorporated public input, the decision was made to build a single-lane modern roundabout at the 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 built a three-leg modern roundabout at this location. This roundabout is large enough to accommodate emergency vehicles, farming equipment, log trucks and other semi-trucks with trailers.

This project permanently closed 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 is open.

WSDOT initially planned to build two roundabouts on US 12 at the intersections of Anderson Road and Moon Road SW. However, the Moon Road roundabout became unnecessary following Thurston County’s intention to close a portion of 188th Avenue SW. 

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. 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 built a modern single-lane roundabout at the intersection of Anderson Road. The roundabout will enhance mobility and travel through the area.

Needs and 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


  • Aug. 2016 - WSDOT open house
  • March 3, 2020  - Project advertised for competitive bidding.
  • April 20, 2020 - Project awarded to Rognlin's, Inc.
  • July 5, 2020 - Construction 
  • Sept. 4, 2020 - Roundabout opened to traffic 
  • Fall 2020 - 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) $2,744
CWA $0
Total $2,744


John Romero
WSDOT Project Office 

Doug Adamson
WSDOT Media Relations 

US 12 Anderson Road-Safety Improvement Project Vicinity Map