Rumble Strips

Rumble strips provide audible and vibratory alerts to drivers whose vehicles have departed the travel lane and warns them that a steering correction is needed.

Gapped milled shoulder rumble strip pattern
Gapped milled shoulder rumble strip pattern (Iowa DOT)

Shoulder rumble strips are narrow, linear bands of indentations (bumps) installed between the travel lane’s edgeline and the paved roadway shoulder. Edgeline rumble stripes are a particular subset of rumble strips installed on the pavements’ edgeline. Rumble strips provide audible and vibratory alerts to drivers whose vehicles have departed the travel lane and warns them that a steering correction is needed. The treatment can be installed on new or existing pavements.

Centerline rumble strips (CLRS) are transverse grooves that are placed along the centerline of a two- or four-lane undivided roadway. These devices can be installed on new, existing, or reconstructed asphalt or portland cement concrete (PCC) pavements.

Similar to shoulder rumble strips, CLRS provide a tactile and audible alert to drivers whose vehicles are crossing the centerline and warns them that a corrective action is needed. Due to their ease of installation and maintenance, CLRS have been found to be useful for reducing the number of

Close-up view of milled shoulder rumble strips
Close-up view of milled shoulder rumble strips (Shauna Hallmark et al./Institute for Transportation)

cross-centerline multi-vehicle crashes at a relatively low cost.

More information about shoulder rumble strips is provided in Chapter 3, and information about edgeline rumble strips is provided in Chapter 4 of Lane Departure Safety Countermeasures: Strategic Action Plan for the Iowa Department of Transportation (Nambisan and Hallmark 2011).

A summary of crash modification factors for shoulder and centerline rumble strips is provided here.

Reference

Nambisan, Shashi and Shauna Hallmark. Lane-Departure Safety Countermeasures: Strategic Action Plan for the Iowa Department of Transportation, Institute for Transportation, Iowa State University, 2011.

Curve with both shoulder and centerline rumble strips
Curve with both shoulder and centerline rumble strips (Shutterstock)
Newly installed shoulder rumble strips
Newly installed shoulder rumble strips (Shutterstock)
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