Where does WSDOT use Rumble Strips?

The Washington State Department of Transportation (WSDOT) uses Roadway Rumble Strips and Shoulder Rumble Strips as a matter of policy.  We are also evaluating Centerline Rumble Strips in a few locations around the state.

Roadway Rumble Strips

May be used at locations such as:

• Stop controlled intersections

• Port of entry/customs stations

• Lane reductions with a history of accidents where driver inattention is a contributing cause.

• Other locations where the character of the roadway changes, such as the end of a freeway.

Shoulder Rumble Strips (SRS) – Divided Highways

WSDOT has a policy for use of SRS on divided highways:

• SRS are required on both the left and the right shoulders of rural interstate highways.

• Consider SRS on both shoulders of other rural divided highways (non-interstate).

 Design exceptions may be granted when:

• Another project scheduled within 2 years of the proposed project will overlay or reconstruct the shoulders, or will use the shoulders as a detour.
• Pavement analysis determines that the pavement structure is inadequate for installation of SRS.
• Shoulders are less than 4’ wide on the left and 6’ wide on the right.

Shoulder Rumble Strips (SRS) – Undivided Highways

WSDOT's policy on the use of SRS on undivided highways is based on criteria driven evaluation, of the following characteristics:

• For use on rural highways with speeds of 45 mph or higher.

• Adequate pavement structure exists on the shoulder.

• Run-off-the-road accident experience is high (guidance provided on evaluation).

• Shoulders are wide enough to provide a minimum of 4’ of shoulder between the SRS and the edge of paved shoulder.  Increase the dimension to 5’ if barrier or guardrail is present at the edge of the shoulder.

• An Engineering analysis indicates the run-off-the-road experience is correctable by installation of rumble strips.

• Must be coordinated with WSDOT’s Bicycle and Pedestrian Advisory Committee.  (BPAC).

Centerline Rumble Strips

WSDOT has developed policy for use of rumble strips as a countermeasure for centerline crossover accidents on state highways.  Sections of US 12, US 395, and state highway 522 have centerline rumble strips installed that are being monitored for their effectiveness.  

Contact Information

Dave Olson, Design Policy, Standards, and Safety Research Manager
Design Policy & Standards @wsdot.wa.gov
360-705-7952  FAX: 360-705-6815
Washington State Department of Transportation Design Office
PO Box 47329
Olympia, WA 98504-7329 

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