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Air Rail Highway Bike/Ped Public Transit
rumble strips

Rumble strips/stripes are a very effective, relatively low cost safety measure intended to deter cross centerline and run off the road crashes.

The New Hampshire Department of Transportation has developed a multi-year plan funded through the Federal Highway Safety Improvement Program (HSIP) to install centerline and shoulder rumble stripes along high volume, undivided state highways to improve safety. The list was developed by staff from Highway Design, Highway Maintenance, and Construction and approved by the Executive Office.

Initially, shoulder rumble strip installation focused on freeways using rolled-in rumble strips of different designs using a modified roller on a pavement rolling machines. Later, paving contractors modified pavement rolling machines to mill rumble strips into existing hardened asphalt pavement. Specifically designed commercially available machines followed.

Rumble strips, also known as sleeper lines, audible lines, "the corduroy", growlers, and "woo woo" boards, are a road safety feature to alert inattentive drivers of potential danger, by causing a tactile vibration and audible rumbling transmitted through the wheels into the vehicle interior. A rumble strip is applied along the direction of travel following an edge line or centerline, to alert drivers when they drift from their lane.

As rumble strips produce audible rumbling in specific audio frequencies based on the spacing of the grooves and the speed of the automobile, they have been used to create novel musical roads. These are also known as "singing shoulders".

The information below is intended to answer some common questions and provide additional information to communities and the general public as to what rumble strips are and why they are installed.

Looking for information relating to rumble strips that isn't listed here?
Contact Ronald Grandmaison at Ronald.Grandmaison@dot.nh.gov

Frequently Asked Questions (FAQ)

Why install rumble stripes?
The main reason is SAFETY!

Nationally,
Center line rumble strips on rural two-lane roads:

  • 44% reduction of head on / fatal and injury crashes;

Center line rumble strips on urban two-lane roads:

  • 64% reduction of head-on / fatal and injury crashes;

Shoulder rumble strips on rural two-lane roads:

  • 36% reduction of run-off -road fatal and injury crashes.

Secondary reasons include:

  • Improve lane positioning
  • Reduce corner cutting through left curves (CRS) and right curves (SRS)
  • Decrease centerline/edge line encroachments

Do rumble stripes cause a disruption to motorcycles?
Center line rumble stripes add no measurable risk to motorcyclists.

Do rumble stripes cause a disruption to bicyclists?
Shoulder rumble stripes are installed on the white line delineating the edge of the travel lane and are being designed to provide adequate width to the right of the shoulder rumble for bicyclists. Gaps are placed in shoulder rumbles for cyclists making turns. Rumble stripes alert bicyclists to vehicles leaving the travel lanes and entering the shoulder area.

Are there any concerns about roadside noise?
Noise from rumble strips occur infrequently (typically when an errant vehicle leaves its lane of travel) and for a short duration. "Jake brakes" or motorcycles make considerably more noise for a longer duration than rumble strips. Rumble stripes save lives and have been dubbed by some states as "the sound of safety." A state of Michigan study indicated an increase in noise levels of 8.1dBA for CRS and 10.1dBA for SRS when contacted during a pass-by of the test vehicle.

Some typical noise levels:

Device dBA
Window Fan on High 60-66
Phone 66-75
Hair Dryer 80-95
Vacuum Cleaner 84-89
Lawn Mower 88-94

 

Are center line rumble stripes installed in passing and no-passing areas?
Yes. Studies indicate there are safety advantages to installing rumble stripes in both areas. Crash Location is random, crash type is not. Lane departures and subsequent crashes occur at random locations and therefore all centerline areas are treated.

Are rumble stripes effective in the winter?
Yes. The snow removal and anti-freezing agents along with the tire action and wind produced from passing vehicles typically remove snow/ice/water caught in grooves. They can also be used as a navigational aide during storms.

Do rumble stripes cause the pavement to deteriorate faster than normal (maintenance)?
Rumble stripes require very little maintenance and NHDOT paving practices have been modified to strengthen joints where rumble stripes are typically milled.

Sound Files
Passenger car driving over rumble strips
(First from outside the vehicle then inside then outside again)

Commercial truck driving over rumble strips
(First from outside the vehicle then inside then outside again)

Informational Presentations
Traffic Safety Conference Meredith, NH 2015

Northeast Safety Conference Providence, RI 2014

Rumble Stripes vs Rumble Strips

Design Information
NHDOT Guidelines for the Installation of Rumble Strips/Stripes

NHDOT Standard Plans

FHWA Technical Advisory T 5040.39: Shoulder and Edge Line Rumble Strips

FHWA Technical Advisory T5040.40: Center Line Rumble Strips

NCHRP Report 641: Guidance for the Design and Application of Shoulder and Centerline Rumble Strips

Additional Web Site Links
USDOT FHWA Office of Safety





New Hampshire Department of Transportation
PO Box 483 | 7 Hazen Drive | Concord, NH | 03302-0483
Tel: 603.271-3734 | Fax: 603.271.3914

copyright 2015. State of New Hampshire