Guidance for the Design and Application of Shoulder and Centerline Rumble Strips (2009) / Chapter Skim
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Pages 134-141
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From page 134... ...
Second, guidance is provided on these issues as they specifically relate to centerline rumble strip policies. Implications on Shoulder Rumble Strip Policies Roadway Types Where it is Appropriate to Install Shoulder Rumble Strips Shoulder rumble strips may be considered for implementation on a wide range of roadway types, including urban freeways, urban freeway on-ramps and off-ramps, urban multilane divided highways (nonfreeways)
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From page 135... ...
As a final note regarding the safety effectiveness of shoulder rumble strips, shoulder rumble strips are expected to reduce SVROR crashes involving heavy vehicles on rural freeways by approximately 40 percent, but no evidence exists to suggest that shoulder rumble strips reduce SVROR involving heavy vehicles on rural two-lane roads. Therefore, if a problem of SVROR crashes involving heavy vehicles is identified along a rural freeway, then installation of shoulder rumble strips can be expected to mitigate these types of crashes.
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From page 136... ...
Also, the use of raised rumble strips is usually restricted to warmer climates due to maintenance difficulties resulting from snow removal in northern climates. Dimensions of Shoulder Rumble Strips For transportation agencies to begin determining the dimensions of shoulder rumble strips, agencies first must start by determining the desired alerting properties of the rumble strip pattern for the given roadway type.
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From page 137... ...
Based upon the results of the safety evaluation of shoulder rumble strips on rural freeways, the results imply that the current dimensions of shoulder rumble strips installed along rural freeways provide sufficient levels of stimuli to alert inattentive and drowsy drivers of heavy vehicles and that it is not necessary to design rumble strip patterns that are "more aggressive" based strictly on the needs of drivers of heavy vehicles.
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From page 138... ...
For other roadway types, such as rural two-lane roads, there is no conclusive evidence to indicate that offset distance impacts the safety effectiveness of shoulder rumble strips. Therefore, based strictly upon the safety benefits, there is no current basis for recommending that transportation agencies change their current policies concerning the placement of shoulder rumble strips with respect to the edgeline on these other roadway types.
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From page 139... ...
When developing a policy on which roadway type or types it is appropriate to install centerline rumble strips, and for help in prioritizing actual sites for the installation of centerline rumble strips, the following criteria have been considered by one or more transportation agencies: – Lane width, – ADT, – Pavement depth, – Area type, – Speed limit, and – Crash frequencies/rates. Valuable information that may help agencies decide on which roadway types they should install centerline rumble strips are reliable estimates on the safety effectiveness of this treatment.
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From page 140... ...
On the other extreme, crash data presented in Section 2, Crashes and Heavy Vehicles, suggest that heavy vehicles should potentially be considered in the design of centerline rumble strips. Designing centerline rumble strips to generate approximately 10 to 15 dBA above the ambient in-vehicle sound level should be more than sufficient to alert drivers of heavy vehicles, based upon the results of the safety evaluation of shoulder rumble strips.
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From page 141... ...
prior to residential/urban areas. Preparation of Centerline Rumble Strips Prior to Overlayment of the Pavement Surface The general principles of the related discussion above for shoulder rumble strips hold true for centerline rumble strips.
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