Travelers near the Thurston/Grays Harbor county line will soon see construction on a new roundabout at the intersection of US 12 and Anderson Road.

Contractor crews working for the Washington State Department of Transportation are scheduled to begin work Monday, July 6, on a project that builds a modern, single-lane roundabout large enough to accommodate emergency vehicles, logging trucks and farm vehicles.

Roundabouts reduce the potential for collisions and this project will make it easier for Anderson Road traffic to merge. Roundabouts also move traffic through an intersection more quickly and with less congestion.

US 12 Anderson Road Safety Improvement Project Map

What travelers can expect during construction
Both US 12 and Anderson Road (south of US 12) will remain open during most of the construction. Drivers can expect lane shifts, alternating traffic controlled by temporary traffic signals and reduced speed limits. Updates about this project will be available online.

The end result
When the work is completed this fall, drivers will use a three-legged single-lane roundabout that accommodates US 12 and Anderson Road south of US 12. Anderson Road north of US 12 will close permanently. Drivers who use that roadway will reach US 12 via Sickman-Ford or Moon Road Southwest.

US 12 – Anderson Rd – Safety Improvement – Fast facts

Will roundabouts create an inconvenience and hinder access for residents?
The proposed design provides the greatest benefit to help reduce the potential for crashes while keeping traffic moving. Modern roundabouts are highly efficient. Unlike a stop sign or a traffic signal, roundabouts offer continuous flow of vehicle traffic.

Will the roundabout affect the local economy by negatively affecting freight?
One of WSDOT’s core functions is to keep people, businesses and the economy moving by operating and improving the state’s transportation systems. Modern roundabouts accommodate all existing big rigs, semi-trucks, and farm equipment. WSDOT will construct what are called truck aprons. These aprons allow large vehicles to go through the roundabout without striking the interior of the roundabout.

Are roundabouts inefficient and unsafe?
WSDOT has installed numerous modern roundabouts on highways across the state since 1997. Roundabouts reduced injury crashes by 75 percent at intersections where stop signs or traffic signals had been used. This is according to a study by the Insurance Institute for Highway Safety (IIHS).

Vehicles can easily enter and exit by following the rules of roundabouts:

Traffic in the roundabout has the right of way.
Vehicles approaching the roundabout yield to traffic inside the roundabout (which approaches from the left).
Drivers yield to pedestrians and bicyclists.

Will these roundabouts be able to handle the high traffic speeds on US 12?
WSDOT will use chicanes (gently curving traffic islands) to help guide and slow traffic as vehicles approach each roundabout.

Will the roundabout create issues for driveway access and limit sight distance?
The new roundabout will have the opposite effect. It will bolster sight distance while eliminating direct conflicts. Direct conflicts are points on the roadway where vehicles traveling or turning in opposing directions could collide.

Why will the proposed roundabout close access to Anderson Road north of US 12?
WSDOT is proposing to build a three-legged roundabout at the intersection of US 12 and Anderson Road. While access to Anderson Road south of US 12 will remain open, access to Anderson Road north of US 12 will close. Building a roundabout that keeps this access open would require costly construction elements to help prevent worsening of flooding. The closure will mean drivers who use this roadway will use either the Sickman-Ford Road or Moon Road Southwest to access US 12.

Will the roundabouts only benefit the Lucky Eagle Casino?
Thousands of drivers rely on US 12 each day between Rochester and Oakville. The proposed roundabout will benefit all users of this important corridor that spans two counties.