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Evaluating
Rural Undivided Highways For Shoulder Rumble Strips
Shoulder Rumble Strips (SRS) are not required on undivided highways, but
may be used where run-off-the-road accident experience is high. SRS
usage on the shoulders of undivided highways demands strategic application
because bicycle usage is more prevalent along the shoulder of the
undivided highway system. Rumble strips affect the comfort and
control of bicycle riders; consequently, their use is to be limited to
highway corridors that experience high levels of run-off-the-road
accidents. Apply the following criteria in evaluating the
appropriateness of rumble strips on the shoulders of undivided highways.
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Use on rural roads only
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Ensure shoulder pavement
is structurally adequate to support milled rumble strips
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Posted speed is 45 mph or
greater
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Ensure that at least 4
feet of useable shoulder remains between the rumble strip and the
outside edge of shoulder. If guardrail or barrier is present,
increase the dimension to 5 feet of useable shoulder.
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Preliminary evaluation
indicates a run-off-the-road accident experience of approximately 0.6
crashes per mile per year, or approximately 34 crashes per 100 million
miles of travel.
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An engineering analysis
indicates a run-off-the-road accident experience considered
correctable by shoulder rumble strips.
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Coordination with WSDOT's
Bicycle and Pedestrian Advisory committee.
Rural Roads
The Highway Road Log provides a desktop reference for which highway
sections are considered rural.
Pavement Structure
Consult the regional Materials Engineer for assistance with this
determination.
Posted Speed of 45 mph or greater
The Highway Road Log provides a listing of posted speed limits for
highway sections.
Shoulder Width
Check the Highway Road Log, and field verify. Identify areas
with barrier along the shoulder edge and consider discontinuing rumble
strips at these locations if clearance is tight.
Crash Experience (Preliminary Evaluation)
Engineering Study
Coordinate with
Bicycle & Pedestrian Advisory Committee
Dave Olson, Design Policy, Standards, and 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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