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Shoulder Rumble Strips
Problem: Roadway departures account for more than half of all roadway fatalities.
Roadway departure fatalities, which include run-off-the road (ROR) and head-on fatalities, are a serious problem in the United States. In 2003, there were 25,562 roadway departure fatalities, accounting for 55 percent of all roadway fatalities in the United States. That same year, more than 16,700 people died in ROR crashes (39 percent of all roadway fatalities). In 2008, 304 persons were killed in noninterstate roadway departure crashes in New York State.
Why are there so many roadway departure crashes?
70 percent of ROR fatalities occur on rural highways, and about 90 percent occur on two-lane roads. Rural highways usually are not as well lit as urban roadways. Inclement weather such as fog, snow, smoke, or dust storms also can decrease the visibility of pavement markings. In these conditions, drivers may drive off the road.
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Potential Solution: Rumble strips are a proven, cost-effective way to help prevent roadway departure crashes.
Shoulder rumble strips have been proven to be a very effective method to warn drivers that they are about to drive off the road. Many studies show very high benefit-to-cost (B/C) ratios for shoulder rumble strips, making them among the most cost-effective safety features available. For example, Nevada found that with a B/C ratio ranging from more than 30:1 to more than 60:1. At approximately $0.30 per foot, rumble strips are more cost effective than many other safety features, including guardrails, culvert-end treatments, and slope flattening.
| At least 40 states are using shoulder rumble strips on secondary highways: |
| Alabama |
Nevada |
| Alaska |
New Jersey |
| Arizona |
New Mexico |
| California |
New York |
| Colorado |
North Carolina |
| Delaware |
North Dakota |
| Florida |
Ohio |
| Georgia |
Oklahoma |
| Hawaii |
Oregon |
| Indiana |
Pennsylvania |
| Iowa |
Rhode Island |
| Kentucky |
South Carolina |
| Maine |
South Dakota
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| Maryland |
Texas |
Michigan  |
Utah |
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Minnesota
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Virginia |
| Mississippi |
Washington |
| Missouri |
Wisconsin
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| Montana |
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| Nebraska |
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| Data provided by NCHRP Report 641: Guidance for the Design and Application of Shoulder and Centerline Rumble Strips and NCHRP Synthesis 490: Practice of Rumble Strips and Rumble Stripes |
NYSDOT began experimental use of shoulder rumble strips in 1978 and made them a common feature on accesscontrolled highways starting in 1995. Placement was limited to freeways. As anticipated, rumble strips produced significant reductions in freeway run-off-the-road (ROR) injuries and fatalities, averaging around a 60% reduction in New York State. A New York study showed a significant change in the number of ROR crashes, injuries, and fatalities after rumble strips were installed on the New York State Thruway. ROR crashes were reduced 88 percent, from a high of 588 crashes in 1993 to 74 in 1997. Total crashes were reduced 87 percent, from a 1992 high of 407 crashes to 54 in 1997. Fatalities were reduced 95 percent, from 17 in 1991 and 1992 to 1 fatality in 1997. While other states also showed positive results, New York's results were better than most.
National Cooperative Highway Research Program (NCHRP 641)  , "Guidance for the Design and Application of Shoulder and Centerline Rumble Strips," summarized the accident reduction experience of three states, Minnesota, Missouri, and Pennsylvania, where significant amounts of shoulder rumble strips had been placed, including rural two-lane roads, and where accident records were sufficient to distinguish trends.
The results varied widely but the researchers concluded that the average safety effects of installing milled shoulder rumble strips on rural two-lane roads were estimated to be a "29-percent reduction in single vehicle run-off-road fatal and injury crashes." The average safety effects of installing milled shoulder rumble strips on rural multilane divided highways were estimated to be a "51-percent reduction in single vehicle run-off-road fatal and injury crashes."
The report also looked at some of the potential hazards of using rumble strips on local roads, and found no link between the use of rumble strips on rural roads and an increase in bicycle crashes.
Cost-Effectiveness:
Cost: Installation is around $0.60 per centerline-foot. To install SHARDs on 2,800 miles = $8.9 M every 10 years (assuming a 10 yr. resurfacing cycle).
Benefit: Installation of SHARDs on Secondary Highways would prevent 4 deaths and approximately 200 injuries/year. This is based on 2006, 2007 and 2008 crash data from NYSDMV on the 2,800 miles of State Highway (about 2.5% of the total highway miles in the state) that meet the proposed installation criteria. Using the average accident costs , SHARDs would save $30M per year and over half a billion dollars in crash costs over 20 years.
The resulting benefit to cost ratio is over 36:1.
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Summaries from Various Studies:
FHWA's Technical Advisory T 5040.39, Revision 1, dated November 2011, states:
"Run-off-road crashes account for approximately one-third of the deaths and serious injuries each year on the Nation's highways. Drift-off crashes, caused by drowsy, distracted, or otherwise inattentive driving, are a subset of run-off-road crashes. [Studies have found that] milled rumble strips are among the most cost-effective countermeasures available for this type of crash, since they directly address driver risk factors."
“Safe accommodation of all road users should be considered when designing and applying rumble strips. This includes passenger and commercial vehicle drivers, bicyclists, pedestrians, and others.”
“Where existing cross-section exists or paved shoulders can be added within the scope of the project, it is preferred to allow at least four feet beyond the rumble strips to the edge of the paved shoulder. Designers should be familiar with the FHWA design guidance found at http://www.fhwa.dot.gov/environment/bikeped/design.htm, which recommends states not install rumbles on new construction and reconstruction projects where shoulders are used by bicyclists unless this condition is met. Where guardrail, curb, or other continuous obstructions exist, additional width may be needed to provide adequate clearance for bicyclists...”
http://safety.fhwa.dot.gov/roadway_dept/pavement/rumble_strips/t504039/ 
"Continued Research on Continuous Rumble Strips." Final Report, Technical Services Division, Maine Department of Transportation, December 1995. Garder, P. & Alexander, J.
This study carried out tests on the effects of milled rumble strips on bicyclists, using two different configurations of milled rumble strips using different riders and several types of bicycles. None of the bicyclists reported any loss of control. Bicyclists reported that riding the rumble strips was annoying, but the study concluded that bicyclists are not faced with dangerous conditions if they mistakenly enter into a rumble strip area. The study stated, "Continuous shoulder rumble strips have a potential to alert wandering drivers and thus reduce the number of run-off-the-road automobile crashes as well as enhance the safety of bicyclists and others using the shoulder."
FHWA's July, 10 2008 memo "Consideration and Implementation of Proven Safety Countermeasures" states:
"The Office of Safety believes that widespread implementation of these safety countermeasures can serve to accelerate the achievement of local, State and national safety goals."
The list of guidance documents included Rumble Strips and Rumble Stripes. The FHWA Guidance on Rumble Strips and Rumble Stripes stated, "Continuous shoulder rumble strips (CSRS) can be applied on many miles of rural roads in a cost-effective manner." http://safety.fhwa.dot.gov/roadway_dept/pavement/rumble_strips/resources/memo_rumstrips071008.cfm
Due to the potential for significantly improved safety for all highway users, NYSDOT is developing a draft policy on the limited installation of shoulder rumble strips on secondary highways.
New York State DOT is evaluating the benefits of installing shoulder rumble strips on a very small percentage of the highway system, where there is a high risk of severe run-off-road crashes, by reviewing research and experiences from other states. In addition to improving motorist safety, there is an expectation that there will be some decrease in the incidence of drivers wandering onto shoulders and striking pedestrians and bicyclists.
Draft criteria limits the installation of shoulder rumble strips to rural, non-freeway highways; with speed limits of 50 MPH and greater; and shoulders 6' and wider. They would also be strongly considered at any locations with a high number of run-off-road accidents. This criteria would limit the installation to approximately 2.5% or 2,800 miles of New York State's total 114,481 miles of highways.
The current draft design guidance for rumble strips on secondary highways differs substantially from freeway rumble strips, to avoid adverse impacts to bicyclists, as follows:
| Feature |
Freeway |
Secondary Roads |
| Posted Speed |
50 mph or more |
50 mph or more |
| Gaps for Bicyclists |
Not Applicable |
12' gap for every 48' of rumble strip |
| Groove Depth |
1/2", 5/8"max |
3/8" with 1/2" max |
| Spacing between Grooves |
12" |
24" |
| Width of Groove |
16" |
12" |
| Offset from the Traveled-Way |
10" on asphalt right shoulders
4" on Portland Cement Concrete and left shoulders
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12"
(Note 1) |
| Remaining Shoulder for Bikes |
N/A |
4' min
(Note 1) |
Notes:
1. Exceptions on facilities with a run-off-the-road crash problem based on a site specific crash study, where a parallel bike facility is within 200’, or the facility prohibits cycling.
For additional information, please
visit the FHWA website:
www.fhwa.dot.gov/crt/lifecycle/rumblestrips.cfm
or contact Richard D. Wilder, P.E.:
Rick.Wilder@dot.ny.gov
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