http://safety.fhwa.dot.gov

FHWA Safety Program

Decision Support Guide for the Installation of 

Shoulder and Center Line Rumble Strips on 

Non-Freeways 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

 

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Notice 

This document is disseminated under the sponsorship of the U.S. Department of 

Transportation in the interest of information exchange. The U.S. Government assumes no 

liability for the use of the information contained in this document. 

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers’ names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement 

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. 

Standards and policies are used to ensure and maximize the quality, objectivity, utility, and 

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TECHNICAL DOCUMENTATION PAGE 

1. Report No. 

FHWA-SA-16-115 

2. Government Accession 

No. 

3. Recipient's Catalog No. 

 

4. Title and Subtitle 

Decision Support Guide for the Installation of Shoulder and Center Line Rumble 

Strips on Non-Freeways 

5. Report Date 

August 2016 

6. Performing Organization Code 

7.Author(s) 

Scott Himes and Hugh McGee 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 

Vanasse Hangen Brustlin, Inc (VHB) 

101 Walnut Street 

Watertown, MA 02471 

10. Work Unit No. 

11. Contract or Grant No. 

GS-00F-116CA, Task DTFH61-15-F00085 

12. Sponsoring Agency Name and Address 

Federal Highway Administration Office of Safety 

1200 New Jersey Ave., SE 

Washington, DC 20590

13. Type of Report and Period 

Guide Book, October 2015 – August 

2016 

14. Sponsoring Agency Code 

FHWA

15. Supplementary Notes 

The contract managers for this report were Abdul Zineddin and Cathy Satterfield. 

16. Abstract 

Center line and shoulder rumble strips are proven safety countermeasures for reducing roadway departure crashes, 

including head-on crashes and run-off-road crashes. The purpose of this guide is to provide a decision-support framework 

to inform center line and shoulder rumble strip installation. It describes methods for identifying appropriate locations for 

installation, assessing the potential crash reductions and benefit-cost ratio, and developing performance metrics for safety. 

Additionally, this guide discusses special considerations for rumble strip installations, identifies variability in current 

practices, and provides a decision-support framework for installing rumble strips. The framework covers policy 

development for systematic rumble strip installation and provides a flowchart for decision-making for sites that can benefit 

from installation but do not meet criteria for systematic installation. The framework can also be applied to sites that are 

identified based on crash history, such as for Highway Safety Improvement Program selection. Within this framework, this 

guide describes who may be involved in the decision-making process, at what points, and provides an overview of safety 

performance measures that can be presented to policy makers and stakeholders. Performance metrics described in this 

guide can be used to inform stakeholders of rumble strip benefits. 

17. Key Words: 

Rumble strips, center line, shoulder, edge line, 

decision making 

18. Distribution Statement 

No restrictions. 

19. Security Classif. (of this report) 

Unclassified 

20. Security Classif. (of this 

page) Unclassified 

21. No. of Pages

 57 

22. Price 

Form DOT F 1700.7 (8-72) Reproduction of completed pages authorized 
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TABLE OF CONTENTS 

INTRODUCTION ....................................................................................... 9

BACKGROUND ............................................................................................................ 9

PURPOSE OF THIS GUIDE ...................................................................................... 10

Intended Audience .................................................................................................... 10

Guide Organization .................................................................................................. 10

Scope of this Guide ................................................................................................... 11

How to Use this Guide ............................................................................................. 11

KEY DEFINITIONS..................................................................................................... 12

Placement .................................................................................................................. 12

Type ............................................................................................................................ 13

Dimensions ................................................................................................................ 14

RUMBLE STRIPS AND SAFETY MANAGEMENT ................................ 15

SELECTING SITES FOR INSTALLATION ............................................................. 15

Systemic Safety Approach ....................................................................................... 15

High Crash Corridor Safety Approach ................................................................... 16

Systematic Safety Approach ................................................................................... 18

IDENTIFYING RUMBLE STRIP EFFECTIVENESS ................................................ 18

CMF Clearinghouse .................................................................................................. 19

Identifying the Most Appropriate CMF(s) .............................................................. 19

Searching for CMFs in the CMF Clearinghouse .................................................... 20

B/C Analysis ............................................................................................................... 22

Example Application 1 – Systemic Installation ..................................................... 24

Example Application 2 – High Crash Corridor Installation ................................. 24

SPECIAL CONSIDERATIONS ................................................................ 26

OVERVIEW OF CURRENT AND SUCCESSFUL INSTALLATION 

PRACTICES ............................................................................................... 29
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CURRENT SYSTEMATIC POLICIES ....................................................................... 29

Shoulder and Edge Line Rumble Strips .................................................................. 30

Center Line Rumble Strips ...................................................................................... 34

SUCCESSFUL HIGH CRASH CORRIDOR INSTALLATION PRACTICES ....... 39

MODEL DECISION-SUPPORT FRAMEWORK FOR RUMBLE STRIP 

INSTALLATION ....................................................................................... 41

OVERVIEW OF MODEL DECISION-MAKING PROCESS ................................... 41

Explanation of Model Decision-Making Process .................................................... 41

CASE STUDIES ......................................................................................... 46

RUMBLE STRIP CASE STUDY FROM MICHIGAN ............................................... 46

Accommodating Amish in Rumble Strip Policy .................................................... 46

Accommodating Pavement Preservation in Rumble Strip Policy ...................... 47

RUMBLE STRIP CASE STUDIES FROM MINNESOTA ........................................ 47

Highway 19 near New Prague ................................................................................. 47

Highway 61 in Northern Minnesota ........................................................................ 47

Highway 14 from Mankato to Nicollet ................................................................... 48

RUMBLE STRIP CASE STUDY FROM TEXAS ...................................................... 49

Systemic Installation of Rumble Strips .................................................................. 49

OTHER RESOURCES ............................................................................... 50

APPENDIX A—EXAMPLE CMF TABLES .............................................. 51

APPENDIX B—DETAILED EXAMPLE APPLICATIONS ..................... 56

Example Application 1 – Systemic Installation ..................................................... 56

Example Application 2 – High Crash Corridor Installation ................................. 57

REFERENCES ............................................................................................ 59
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List of Tables 

Table 1. Agency systemic SRS installation criteria. ..................................................... 32

Table 2. Agency systematic center line rumble strip installation criteria. ............... 37

Table 3. Sample CMF Clearinghouse CMFs for CLRS on rural, two-lane highways.

 ........................................................................................................................................... 52

Table 4. Sample CMF Clearinghouse CMFs for SRS on rural, two-lane highways. .. 53

Table 5. Sample CMF Clearinghouse CMFs for SRS on rural, multilane highways. 54

Table 6. Sample CMF Clearinghouse CMFs for CLRS and SRS on rural, two-lane 

highways. ........................................................................................................................... 55

 List of Figures 

Figure 1. Photograph. Combination milled CLRS and SRS. ....................................... 12

Figure 2. Photograph. Example profiled thermoplastic pavement marking. ........... 13

Figure 3. Illustration. Rumble strip dimensions.(6) ....................................................... 14

Figure 4. Screen capture. CMF Clearinghouse comparison for CLRS. ..................... 22

Figure 5. Equation. Conversion from 2001 dollars to 2015 dollars. ........................... 23

Figure 6. Equation. Present value of uniform annual benefit or cost. ....................... 23

Figure 7. Illustration. SRS rumble strip dimensions.

(6) ................................................ 31

Figure 8. Illustration. CLRS rumble strip dimensions.(6) ............................................. 36

Figure 9. Illustration. Model decision-making framework for rumble strip 

installation. ....................................................................................................................... 42

Figure 10. Photograph. Buffer median on Highway 14 from Bing Streetside.(20) ..... 49
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ACRONYMS 

AADT annual average daily traffic 

B/C benefit-cost 

CLRS center line rumble strip 

CMF crash modification factor 

CRF crash reduction factor 

DOT Department of Transportation 

EB empirical Bayes 

ELRS edge line rumble strip or stripe 

FARS Fatality Analysis Reporting System 

FHWA Federal Highway Administration 

HSIP Highway Safety Improvement Program 

HSM Highway Safety Manual 

MDOT Michigan Department of Transportation 

MnDOT Minnesota Department of Transportation 

NCHRP National Cooperative Highway Research Program

ROR run-off-road 

RPM raised pavement marking 

RTM regression-to-the-mean 

SPF safety performance function 

SRS shoulder rumble strip 

TxDOT Texas Department of Transportation 
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INTRODUCTION 

BACKGROUND 

Center line and shoulder rumble strips are proven safety countermeasures for reducing 

roadway departure crashes, including head-on crashes and run-off-road (ROR) crashes. 

According to a recent study, ROR left or right crashes account for 64.4 percent of all singlevehicle crashes and, of those, 95.1 percent of the time the critical reasons were driver 

related.(1) Further analysis indicated the dominant critical reasons for passenger cars were 

internal driver distraction, steering overcompensation, poor directional control, too fast for 

curve, and sleeping. The dominant critical reason for large trucks was sleeping. According to 

the Fatality Analysis Reporting System (FARS) data, approximately 55 percent of fatal crashes 

are those targeted by rumble strips.(2) Moreover, for rural two-lane highways, that number

increases to approximately 66 percent. According to a 2009 National Highway Traffic Safety 

Administration study using events from the 100-Car Naturalistic Driving Study, approximately 

66 percent of ROR events were departures to the right and 31 percent were to the left.(3)

Furthermore, Leuer found, using 2009 to 2013 data, that 13.4 percent of fatal crashes on 

Minnesota rural, two-lane highways were ROR left and 16.7 percent were ROR right, indicating 

that center line rumble strips are as important at preventing ROR crashes as shoulder rumble 

strips.(4) In a separate study, Leuer found that while head-on crashes account for only 5 percent 

of crashes on Minnesota rural, two-lane highways, they account for more than 18 percent of 

the fatal crashes.(5) Further analysis indicated that approximately 65 percent of fatal head-on 

crashes were the result of the vehicle drifting over the centerline and 31 percent were the 

result of control loss. 

Rumble strips are a relatively low-cost countermeasure and economic analyses have indicated 

benefit-cost (B/C) ratios that exceed 100 to 1 (i.e., 100 dollars saved for every 1 dollar spent). 

For this reason, shoulder rumble strips have been installed nearly system wide for the 

Interstate system and most freeways and expressways. However, agencies have had varying 

degrees of success installing center line and shoulder rumble strips on multilane and two-lane 

roadways. The three primary concerns for rumble strips for these highway types include the 

following: 

• Inconvenience for bicyclists. Standard rumble strip dimensions used by most agencies 

are difficult to traverse if bicycle gaps are not provided, as they make the rider 

uncomfortable and may lead to loss of control. 

• External noise pollution. Rumble strips alert motorists through noise and vibration. The 

noise generated by rumble strips is different than background traffic noise and is 

intermittent. This can create a disturbance for nearby residents and for special 
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environmental conditions (e.g., noise-sensitive wildlife habitats) if there are frequent 

incidental contacts. 

• Pavement durability. There is concern that milling rumble strips into longitudinal joints 

or into the wearing course will allow water infiltration causing premature pavement 

deterioration. 

PURPOSE OF THIS GUIDE 

The purpose of this guide is to inform agencies on center line and shoulder rumble strip 

installation. It describes methods for identifying appropriate locations for installation, assessing 

the potential crash reductions and B/C ratio, and developing performance metrics for safety. 

Additionally, this guide discusses special considerations for rumble strip installations, identifies 

variability in current practices, and provides a decision-support framework for installing rumble 

strips. 

The framework covers policy development for systematic rumble strip installation and provides 

a flowchart for decision-making for sites that can benefit from installation but do not meet 

criteria for systematic installation. Rumble strips fulfill a systemic need; however, the 

framework is also applied to sites that are identified based on crash history, such as for 

Highway Safety Improvement Program (HSIP) selection. Within this framework, this guide 

describes who may be involved in the decision-making process, at what points, and provides an 

overview of safety performance measures that can be presented to policy makers and 

stakeholders. Performance metrics described in this guide can be used to inform stakeholders 

of rumble strip benefits. 

Intended Audience 

This guide is intended for practitioners in transportation planning, highway design, traffic 

operations, highway maintenance, and traffic safety concerned with reducing target crashes 

through the installation of center line and shoulder rumble strips. This includes practitioners in 

Federal, State, local, and Tribal agencies tasked with improving highway safety using proven, 

low-cost, safety strategies. This also includes consultants working for these agencies. 

Guide Organization 

The guide is organized as follows: 

• Introduction. This section provides background on the safety countermeasure, the 

purpose of the guide, and key definitions related to rumble strips. 
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• Rumble strips and safety management. This section discusses the methodologies for 

implementing rumble strips as a safety countermeasure and methodologies for 

estimating the safety effectiveness and economic impact. 

• Special considerations. This section discusses key factors related to the impacts of 

rumble strips on bicyclists and motorcyclists, noise impacts on nearby residents, and 

perceived impacts to pavements. 

• Overview of current and successful practices. This section identifies current practices 

agencies use for installation of rumble strips and identifies successful practices and 

methods for installing rumble strips based on high crash corridor analyses. 

• Decision-support framework for rumble strip installation. This section provides a 

framework for agencies to follow based on current successful practices of agencies with 

widespread rumble strip installation. 

• Case studies. This section includes case study examples where agencies weighed the 

decision to install rumble strips when there was potential concern for roadway users 

other than vehicles, nearby residents, and pavement condition. 

• Other resources. This section provides links to related resources. 

Scope of this Guide 

The information presented in this guide focuses on rural, non-freeway applications. Additional 

information is presented for urban areas as appropriate. The guide does not focus on freeways, 

as there are fewer trade-off concerns and agencies have generally been successful at installing 

rumble strips on these facilities. The guide supports the installations of both center line and 

shoulder rumble strips. 

How to Use this Guide 

It is recommended that the entire guidance document be reviewed before application. This 

guide provides an overview of installation approaches and provides methodology for selecting 

high crash corridors for treatment, estimating countermeasure effectiveness, and conducting 

B/C analysis. These methods can be used to inform decision-making for the following: 

• Systemic safety issues. 

• HSIP selections. 

• Recommendations stemming from road safety audits. 

• Trade-off analysis when considering multiple options for treatment or non-treatment. 
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Additionally, this guide provides an overview of current agency practices and a model decisionmaking framework for installing rumble strips. This information can be used to inform rumble 

strip policy development and for identifying alternative designs for rumble strip installation 

where the standard practice cannot be applied. 

KEY DEFINITIONS 

This section introduces important concepts and characteristics of rumble strips. Rumble strips 

are characterized by their location, type, and dimensions. Each of these characteristics are 

described in greater detail in the subsections that follow.

Placement 

Rumble strip placement is defined as center line (CLRS), shoulder (SRS), or their combination 

(CLRS+SRS). SRS can be further defined by their offset from the edge line pavement marking. If 

the SRS is applied in conjunction with the pavement marking, then it is characterized as an edge 

line rumble strip or stripe (ELRS). If the SRS is located outside the pavement marking, then it is 

simply referred to as SRS. Throughout the document SRS and ELRS are collectively referred to 

as SRS, unless specifically talking about ELRS. Figure 1 shows and installation of combined CLRS 

and SRS. 

Transverse rumble strips are placed within the lane to warn drivers of upcoming unexpected 

changes, such as traffic signals, changes in alignment, or the need to change lanes. Transverse 

rumble strips are not a focus application for this guide and will not be discussed further. 

Figure 1. Photograph. Combination milled CLRS and SRS. 
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Type 

Currently, there are two main types of rumble strips used on rural, non-freeway facilities, 

milled and raised. Milled rumble strips, which are most prevalent, are milled into the roadway 

surface using a rotary milling machine. They function by allowing the tire to drop into the 

groove, which creates both sound and vibration. The sound level has been studied and has been 

shown to be a function of the dimensions of the milled rumble strip, which are explained in the 

next section. Figure 1 provides an example of milled rumble strips. Recently, some agencies 

have also begun studying and specifying dimensions for milled sinusoidal rumble strips, which 

are intended to reduce the external noise produced while providing sufficient noise and 

vibration to alert the driver of roadway departure. 

Although research suggests that milled rumble strips are the most effective application type, 

raised rumble strips have been applied in States with warmer climates in cases where milled 

rumble strips cannot be installed. Raised rumble strips include side-by-side raised pavement 

markers, rumble bars, or plastic inserts within thermoplastic pavement markings. Profiled 

thermoplastic pavement markings have been developed to help with nighttime, wet visibility 

and, may have some very limited rumble characteristics. Figure 2 provides an example of 

profiled thermoplastic pavement markings in Washington. Locations without snowplowing 

activities may use profiled thermoplastic pavement markings or other raised rumble strips; 

however, milled rumble strips are preferred. Raised rumble strips may be considered in areas 

where milled rumble strips are not practical, such as bridge decks or on thin surface courses 

(e.g., chip seals). 

Figure 2. Photograph. Example profiled thermoplastic pavement marking. 
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Dimensions 

Figure 3 provides a graphical representation of rumble strip dimensions, which is explained as 

follows:(6)

A. Offset: This is the distance from the pavement marking (delineating the edge of the 

traveled way) to the inside edge of the rumble strip. 

B. Length: Dimension of the strip that is perpendicular to the travel directions of the 

roadway. This is often referred to as the transverse width of the rumble strip. 

C. Width: Dimension of the strip that is parallel to the travel direction of the roadway. 

D. Depth: The maximum distance from the surface of the roadway to the bottom of the 

rumble strip. 

E. Spacing: The distance between adjacent rumble strips. It is most often measured from 

the center of the strip to the center of the adjacent strip. 

F. Gap: The distance from edge of rumble strip to edge of rumble strip when there is a 

break in the pattern. Gaps are commonly used to allow bicycles to cross the rumble 

strip pattern, to allow passing vehicles to cross CLRS, and to allow for turning 

movements at intersections and driveways. 

Figure 3. Illustration. Rumble strip dimensions.(6)
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RUMBLE STRIPS AND SAFETY MANAGEMENT 

SRS and CLRS on rural, two-lane highways are proven safety countermeasures. National 

Cooperative Highway Research Program (NCHRP) Report 641: Guidance for the Design and 

Application of Shoulder and Centerline Rumble Strips documented significant crash reductions 

for SRS and CLRS on rural, two-lane highways. SRS were found to provide a 36-percent 

reduction in ROR fatal and injury crashes while CLRS were found to provide a 44-percent 

reduction in head-on fatal and injury crashes.(7) However, researchers have found that rumble 

strips are not equally effective for all roadway geometries and traffic volumes. Additionally, 

rumble strips can be used to target drowsy or distracted driving, while other roadway 

treatments do not fulfill this need. Rumble strips are most effective and should be considered in 

corridors with the greatest need. This section provides an overview of methodologies for 

selecting sites for installation, identifying rumble strip effectiveness, and conducting B/C analysis 

for treatments. 

SELECTING SITES FOR INSTALLATION 

Roadway departure crashes, which include ROR crashes and head-on crashes, are typically a 

systemic problem, meaning that they account for a high number of crashes, but their density is 

often low. High crash locations often prove to be difficult to identify, although more success can 

be found in identifying high crash corridors. As noted in the Low Cost Treatments for 

Horizontal Curve Safety 2016 the most effective safety improvement processes include both a 

systemic component and site analysis, or in this case, corridor analysis component.(8)

Additionally, agencies utilize an additional systematic component for installing rumble strips 

based on agency-level policy. 

Systemic and corridor analyses are most commonly used to identify corridors for retrofit 

installations. Retrofit installations are projects in which the objective is to install rumble strips 

where they did not previously exist. Systematic analyses are most commonly used for installing 

rumble strips on new, reconstructed, or resurfaced roadways (i.e., rumble strips are applied on 

corridors while on-site performing other activities). Each of these approaches is defined below 

and explained in further detail in terms of rumble strip safety. 

Systemic Safety Approach 

Using the systemic safety approach, agencies implement rumble strips on corridors based on 

risk features that are correlated with higher severity focus crash types (e.g., K and A severities 

on the KABCO scale). In this approach, corridor crash history is not considered for identifying 

rumble strip treatment locations. Rather, crash data analyses are used to identify risk factors 

associated with fatal and severe injury ROR crashes, fatal and severe injury head-on crashes, or 

other focus crashes outcomes. Severe crash types are typically addressed using a systemic 
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approach since they are often less concentrated than total crashes, but tend to be overrepresented at locations with more risk factors. Risk factors for severe ROR crashes often 

include characteristics such as lane width, shoulder width, and traffic volume, among others. 

Analyses are conducted across all corridors within a facility type (e.g., rural, two-lane highways) 

to identify factors that contribute to increased risk of focus crash outcomes. Risk factors may 

be combined in a weighted manner to identify specific corridors for treatment. 

For example, analysis of all rural, two-lane highway corridors within a jurisdiction may identify 

risk factors for fatal and severe ROR crashes as being annual average daily traffic (AADT) 

greater than 400 and less than 2,000, lane width less than 12 feet, shoulder width less than 4 

feet, curve density greater than 2 curves per mile, and roadside hazard rating greater than 3. 

The jurisdiction may prioritize corridors with all of these risk factors for rumble strip 

installation or may develop weights for each risk factor and prioritize segments with the highest 

combined ranking of risk factors within a given budget. 

High Crash Corridor Safety Approach 

Agencies have traditionally used crash frequency (e.g., locations with a high number of crashes 

or higher than expected number of crashes) to justify additional corridors for installing rumble 

strips on an as-needed basis. This approach may also be referred to as a case-by-case approach 

because installation must be considered for each corridor based on multiple factors, and the 

decision to install or not is made independently in each instance based on these factors. 

Agencies often consider the crash rate in relation to the statewide average to determine if a 

corridor should be examined further for rumble strip installation. Most often, they base 

installation recommendations on three to five years of historical crash data. 

The Highway Safety Manual (HSM) defines the crash rate as “the number of crashes that occur 

at a given site during a certain time period in relation to a particular measure of exposure.” (9)

Commonly this is computed as the average crash frequency, or crashes per year, divided by the 

average traffic volume (expressed as AADT) for the same time period. At this point, the crash 

rate for a corridor is compared to the average crash rate for all corridors within the specific 

facility type (e.g., rural, two-lane highways). Typically, the corridors with the highest crash rates 

or crash rates that are above average are selected for treatment. This methodology is simple to 

employ; however, it suffers from the following limitations: 

• It assumes that the impact of traffic volumes is linear, which has been shown through 

many studies to not be a valid assumption, particularly for rural, two-lane highways. 

Crash rates should not be compared for roadways with significantly different AADTs. 

• It does not account for regression-to-the-mean (RTM) bias. This methodology will tend 

to focus on corridors with a short-term rate that is above average; which, for two-lane 

rural highways could be subject to one year with an abnormal number of crashes. 
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• It can focus on low-volume roadways that have had one crash in the study period. Many 

research studies have found that rumble strips are more effective on roadways with 

higher AADTs, and the influence of one crash can be large for roadways with very low 

AADTs. 

• The average crash rate for all corridors is not the most valid threshold for comparing to 

the predicted number of crashes for corridors with similar characteristics. Safety 

performance functions (SPFs) provide a more rigorous approach to identifying predicted 

crashes at similar corridors. 

SPFs provide the predicted number of crashes for corridors based on data from corridors with 

similar characteristics, and is a function of the AADT and corridor length. SPFs account for the 

non-linear relationship between traffic volume and crash frequency, as well as potential 

differences in characteristics for short versus long corridors. As noted in the HSM, the SPF 

prediction can be utilized for several methods for identifying high crash corridors that are more 

statistically valid than the crash rate method.(9) The following performance measures utilize 

SPFs: 

• Level of Service of Safety. 

• Excess Predicted Average Crash Frequency using SPFs. 

• Expected Average Crash Frequency with empirical Bayes (EB) adjustment. 

• Equivalent Property Damage Only Average Crash Frequency with EB adjustment. 

• Excess Expected Average Crash Frequency with EB Adjustment. 

The Excess Predicted Average Crash Frequency using SPFs is the easiest to compute, as this 

performance measure simply compares the difference between the SPF predicted average crash 

frequency and the observed average crash frequency. However, this performance measure 

cannot account for RTM bias. The Excess Expected Average Crash Frequency with EB 

Adjustment performance measure goes one step further, to calculate the expected average 

crash frequency. The expected average crash frequency is a weighted average of the observed 

average crash frequency and predicted average crash frequency from the SPF. The expected 

average crash frequency accounts for RTM bias. The expected average crash frequency is 

compared to the predicted average crash frequency and the difference is the excess expected 

average crash frequency. If this value is greater than zero, then a site experiences more crashes 

than is expected and may be a better candidate for an improvement. See Chapter 4 of the HSM 

for more details on performance measures and their strengths and limitations. 
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Systematic Safety Approach 

While the systemic approach to safety focuses on identifying locations for rumble strip 

installation based on risk, the systematic approach to safety focuses on installing rumble strips 

system-wide, often while completing other construction activities, with exceptions to 

installation that are based on policy. Most agencies have policies outlining criteria for systematic 

rumble strip installation. Criteria for installation are based on special considerations, including 

accommodating bicycles, minimizing noise disturbance, and avoiding potential pavement quality 

issues. For CLRS, the systematic approach is typically based on pavement condition, posted 

speed limit, and lane or pavement width. For SRS, the systematic approach is typically based on 

pavement condition, posted speed limit, shoulder width, and presence of curb or guardrail. 

Posted speed limit is often used as a surrogate measure for built-up environment. 

IDENTIFYING RUMBLE STRIP EFFECTIVENESS 

Rumble strip safety effectiveness is established through the development and use of crash 

modification factors (CMFs). A CMF is an index of the expected change in safety performance 

following a change in traffic operations or installation of a countermeasure. The percent change 

in crashes is calculated as 100*(1-CMF); thus, a CMF of 0.70 with a standard deviation of 0.12 

indicates a 30 percent reduction in crashes with a standard deviation of 12 percent. 

Users may apply the CMF directly to the expected number of crashes without treatment to 

estimate the number of crashes with treatment, or to estimate the change in crashes. 

Alternatively, the upper limit of the confidence interval provides a conservative estimate of the 

expected change in crashes. The upper 95-percent confidence limit of the CMF is determined 

by multiplying the standard deviation by 1.96 and adding this to the CMF. [Note this is 

approximated by CMF+2×standard error.] In this example, the analyst can use 0.70 or a 

conservative value of 0.94. Users may choose to use the upper limit if the CMF is of lower 

quality (explained in further detail in the next section) or if it is unlikely that the specified 

reduction can be achieved. 

The CMF Clearinghouse and the HSM Part D contain CMFs for center line and shoulder 

rumble strips and their combination. Part D of the HSM contains CMFs that passed a screening 

process or met expert panel approval for adequate reliability and stability. The CMF 

Clearinghouse is a living website that contains all CMFs for treatments, including those in the 

HSM Part D. The CMFs in the Clearinghouse range from high quality to low quality. The 

Clearinghouse is updated quarterly and contains the most up-to-date CMFs related to rumble 

strips on all facility types. Further information about CMFs in the Clearinghouse is presented in 

the next section. 
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CMF Clearinghouse 

There are more than 500 research-based CMFs relevant to rumble strips located in the CMF 

Clearinghouse. This section provides a brief overview of identifying the most appropriate CMFs 

and searching for CMFs in the CMF Clearinghouse. More details on using the CMF 

Clearinghouse are located at www.cmfclearinghouse.org; select the “About the CMF 

Clearinghouse” tab. 

Identifying the Most Appropriate CMF(s) 

Having identified the countermeasure of interest, the user navigates a list of CMFs to identify 

which CMF best approximates the reduction that can be expected for proposed installation or 

policy. CMFs can be generally applicable (e.g., all rural, two-lane highways), or may be specific to 

a unique set of factors (e.g., rural, two-lane highway horizontal curves with a shoulder width 

less than or equal to five feet). The applicable factors may be found in the countermeasure 

name or they may be buried in the CMF details. The CMF details are discussed in more detail in 

the “Searching for CMFs” in the CMF Clearinghouse section. 

Major factors in identifying the most relevant CMF include the following: 

• Countermeasure name. The countermeasure name may be more general and widely 

applicable, or in some cases, specific, immediately narrowing the applicability of the 

CMF. The countermeasure name will specify if the CMF applies to CLRS, SRS, or their 

combination. 

• Number of lanes and area type. These two factors, used in combination, specify the 

appropriate facility type targeted by the countermeasure for the CMF. Often, one or 

both of these factors may be left blank, indicating that the information was not provided. 

Alternatively, these factors may show that the CMF applies to multiple facility types 

rather than targeting one specific facility type. 

• Crash type. The CMF may be developed for all (i.e., total) crashes or for a specific crash 

type. CLRS typically target head-on crashes (and ROR left) while SRS typically target 

ROR crashes. Analysts should identify the crash type of interest when comparing CMFs. 

• Crash severity. As with crash type, CMFs can be developed for all severities or for a 

specific set of severity levels (e.g., fatal and injury crashes). Analysts should identify the 

appropriate crash severity when comparing CMFs. 

Additional factors may be used to help narrow the list of applicable CMFs for rumble strips. 

The following list includes additional minor factors used to help identify the most applicable 

CMF. 

• Speed limit. 
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• Traffic volume (minimum and maximum). 

• Time of day. 

• Jurisdiction(s). 

• Geometric character. 

CMFs are often developed for a specific value of minor characteristics or the researchers will 

provide the values of minor characteristics for which the CMFs were developed. However, 

some minor factors, such as speed limit, are often unreported. The reported minor factors for 

the CMFs can be used to identify which is closest to the applicable scenario if multiple CMFs 

remain after screening based on the major factors. Traffic volumes and jurisdictions (most often 

States) are reported for many CMFs. Geometric characteristics may be more difficult to 

determine—see the “Searching for CMFs” in the CMF Clearinghouse section for more 

details—however, geometric characteristics, such as applicability for horizontal curves or for 

certain shoulder widths are available for several CMFs. 

In addition to relevance, CMFs are characterized based on quality. The quality is provided as a 

star rating. The CMF may be rated from 0 to 5 stars, with higher quality CMFs having a higher 

star rating. Higher quality CMFs control for potential biases, have larger sample sizes, and are 

more generalizable (i.e., are developed from more diverse geography). Sample 5-star and 4-star 

CMFs from the CMF Clearinghouse are provided in Appendix A for CLRS, SRS, and their 

combination. These CMFs represent the highest quality currently available in the CMF 

Clearinghouse and provide an example of the breadth in applicability for CMFs in the 

Clearinghouse. See Appendix A for further details and descriptions of information available for 

the sample CMFs. 

Searching for CMFs in the CMF Clearinghouse 

This section discusses searching the CMF Clearinghouse for the most appropriate CMF based 

on the factors covered in the Identifying the Most Appropriate CMF(s) section. This discussion 

is focused on using the website to identify CMFs specifically for rumble strips. For further 

information, visit the CMF Clearinghouse website. 

The CMF Clearinghouse homepage allows users to search for CMFs based on the 

countermeasure name, research study information, and CMF ID. The countermeasure name 

will be the most useful for most practitioners, and specificity in search terms is important. For 

example, if searching “rumble strip,” the search will return (at the time of this publication) 

more than 500 CMFs. If looking for CMFs related to CLRS, entering “center line rumble strips” 

returns more than 100 CMFs. Leaving the search terms blank will return all CMFs in the 

clearinghouse. 
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Having conducted a search, users can browse the returned CMFs by category (e.g., roadway) 

and subcategory (e.g., roadway rumble strips). Additionally, users can filter the search to 

include only CMFs of a certain star rating or other major factors. Using the filtered list, users 

can explore the remaining countermeasures for applicable CMFs. Countermeasure names may 

vary in terms of specificity, and it is possible more than one countermeasure name will apply to 

a search. At this point, the CMF, quality, crash type, crash severity, and area type are presented; 

users can choose to select one CMF for further details, or can select a check box to compare 

multiple CMFs. 

When selecting one CMF for further evaluation, the CMF/crash reduction factor (CRF) details 

page will appear. This contains information on the following relevant CMF characteristics: 

• Star Quality Rating. 

• CMF/CRF. 

• Applicability. 

• Development Details. 

• Other Details. 

The applicability section defines several important major and minor factors for which the CMF 

is appropriate. The section provides details on the applicable crash type, crash severity, 

roadway types, number of lanes, road division type, speed limit, area type, traffic volume, and 

time of day for the CMF. The development details section provides further useful information 

for selecting an appropriate CMF, including the municipality(ies), State(s), or country(ies) from 

which the CMF was developed. If multiple CMFs are relevant, the selection may be made on the 

State or municipality that is more similar to the user’s State or municipality. Finally, the other 

details section includes comments related to the CMF. The comments box is used to provide 

further information on other details of the CMF that do not fit into the other categories. For 

example, there may be comments on whether the CMF applies only to horizontal curves or 

tangents among other potential geometric characteristics. 

Alternatively, multiple CMFs may be applicable, and users can select up to six for comparison. 

The comparison function provides side-by-side details of the major and minor factors and 

highlights any differences with a light blue bar. The light blue bars can be used to look for 

differences, and the countermeasure name and the comments section can be reviewed for any 

further details that will help to identify the most appropriate CMF. 

Figure 4 provides an example comparison for CLRS. Consider a scenario where a user is 

interested in determining the CMF for CLRS for all fatal and injury crashes on rural, two-lane 

highways with curves. CMF ID 3387 is not applicable because the crash type and severity do 

not match the desired scenario. CMF IDs 3350 and 3383 apply to the same crash type and 
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severities (and are identical for all other factors not shown here). However, from the 

countermeasure name, CMF ID 3350 applies to general roadway corridors while CMF ID 3383 

applies only to tangent sections (i.e., non-curve locations). In this case, the user would select 

the first CMF of 0.91 for further evaluation because the desired scenario includes both tangents 

and curves. 

Figure 4. Screen capture. CMF Clearinghouse comparison for CLRS. 

B/C Analysis 

A B/C analysis is an important tool for determining if the proposed treatment is worthwhile. 

The B/C analysis compares the present value of annual benefits divided by the present value of 

total costs. Total costs include installation costs and annual operating or maintenance costs. A 

ratio greater than 1.0 indicates the benefits are greater than costs and a ratio less than 1.0 

indicates the benefits are less than costs. 

The safety benefits for rumble strips are measured by the change in crash costs, which is 

computed by multiplying the change in crashes per year by the average cost of a crash. It is 

important to note the average crash cost should match the crash type used in the analysis. For 

example, if the CMF is for fatal and injury crashes, then the average crash cost should reflect 

the cost for fatal and injury crashes, not all crashes. The FHWA report Crash Cost Estimates by 

Maximum Police-Reported Injury Severity within Selected Crash Geometries provides crash costs by 

severity level, crash geometry, and speed limit, based on 2001 dollars.(10) The HSM also provides 

crash costs by severity level, which are based on the FHWA report. The 2001 values can be 

updated using the ratio of most recent United States Department of Transportation value of a 
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statistical life and the 2001 value of 3.8 million dollars. Using the 2015 value (9.4 million dollars), 

the unit cost multiplier is approximately 2.47 as shown in Figure 5. 

Figure 5. Equation. Conversion from 2001 dollars to 2015 dollars. 

From the FHWA report, the 2001 average cost for a property damage only crash is 7,428 

dollars and the average cost for a fatal or injury crash is 158,177 dollars. If a corridor targeted 

for SRS has a 2001 weighted (by severity) crash cost of 82,803 dollars, then the updated 

average crash cost would be 204,523 dollars (82,803 × 2.47). The annual benefit is computed by 

multiplying the average crash cost by the estimated change in crashes per year. 

The present value is computed by multiplying the annual benefit or cost by the Capital 

Recovery Factor, as shown in Figure 6. 

Figure 6. Equation. Present value of uniform annual benefit or cost. 

Where: 

 = annual benefit or cost. 

= inflation rate. 

 = service life. 

The present value equation applies only to annual costs and is not applied to the installation 

cost. The service life for rumble strips is often assumed to be the time until the next pavement 

overlay, unless the rumble strip is deemed to still be effective after a thin overlay or chip seal. 

Most commonly, the service life is reported to be 7 to 10 years, but has been reported to be as 

high as 15 to 20 years. The Office of Management and Budget Circular A-4 suggests a 

conservative real discount rate of 7 percent for .

(11)

Rumble strip installation costs vary widely among and within States. Unit prices for rumble 

strips range between 500 dollars and 6,000 dollars per mile. There are many factors that can 

influence the cost, and they are provided in detail on the FHWA Rumble Strips and Rumble 

Stripes website.

(12) For economic analysis, agencies can use historical data for installations to 

determine an average installation unit price. Typically, the unit price for SRS is for one side of 

the road, and would be multiplied by two for installation on both shoulders for two-lane 

roadways, or on the inside and outside shoulder for a directional analysis of multilane roadways. 

2015 	

 = 2001 	

 ∗ 2.47



 	

 =  ∗

(1 + )

 − 1

∗ (1 + )


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Example Application 1 – Systemic Installation 

An agency has identified 7,500 miles of rural, two-lane highways for retrofit installation of ELRS. 

Before recommending installation, a B/C ratio was calculated. The necessary assumptions for 

analysis are provided below as well as the results of the study. See Appendix B for details on 

calculating the results shown. The analysis focuses on fatal and injury ROR crashes. 

Assumptions: 

• ELRS cost per mile: 1,500 dollars per line. 

• Annual fatal and injury ROR crashes: 125 crashes. 

• Rumble strip life expectancy: 7 years. 

• CMF for ELRS for fatal and injury ROR crashes: 0.67.

• 2001 crash cost for fatal and injury crashes: 158,177 dollars. 

Results: 

• Annual crashes reduced: 41.25. 

• 2015 crash cost for fatal and injury crashes: 390,697.20 dollars. 

• Annualized construction cost: 4,174,947 dollars. 

• Annual benefits: 16,116,259 dollars. 

• B/C ratio: 3.86. 

The results indicate that while the targeted facilities experience an average 0.017 fatal and injury 

ROR crashes per mile, the installation is economically justified. The analysis indicates that 

approximately 41 fatal and injury ROR crashes would be reduced per year. 

Example Application 2 – High Crash Corridor Installation 

For a 2.5-mile section of rural, two-lane highway, an analyst identified the following information 

from a roadway inventory, crash database, and safety performance function: 

• AADT 5,500. 

• 2012 ROR Crashes: 8 Observed, 3.67 Predicted. 

• 2013 ROR Crashes: 7 Observed, 3.67 Predicted. 

• 2014 ROR Crashes: 9 Observed, 3.67 Predicted. 

• Percent fatal and injury ROR crashes: 50 percent. 
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Given information for CLRS and SRS include the following: 

• CMF for ROR crashes: 0.70. 

• 2001 crash cost for fatal and injury crashes: 158,177 dollars. 

• 2001 crash cost for property damage only crashes: 7,428 dollars. 

• Installation cost: 1,500 dollars per mile. 

• Rumble strip life expectancy: 7 years. 

Results: 

• Expected number of ROR crashes: 5.88 crashes/year. 

• Excess expected ROR crashes: 2.21 crashes/year = candidate for CLRS and SRS. 

• Annual crashes reduced per mile: 0.70 crashes/mile.

• 2015 crash cost for fatal and injury crashes: 204,522 dollars per crash. 

• Annualized construction cost: 835 dollars per mile.

• Annual benefits: 143,984 dollars. 

• B/C ratio: 172.4. 

The upper 95-percentile estimate of the CMF is 0.79, resulting in a reduction of 0.49 ROR 

crashes per mile per year. The annualized benefit is calculated to be 101,018 dollars per mile. 

The resulting B/C ratio is 121.0, indicating that even a conservative estimate of the reduction 

results in a highly cost-effective solution. 
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SPECIAL CONSIDERATIONS 

While rumble strips help reduce ROR crashes and are a proven low-cost safety 

countermeasure, they can negatively impact bicyclist activity, generate disturbing noise, and may 

impact pavement quality or future maintenance activity. These special considerations are 

generally acknowledged in agency policies and are covered in the FHWA Rumble Strips and 

Rumble Stripes website.

(12) The website contains implementation fact sheets targeting those 

involved in rumble strip design or installation and contains implementation guides targeting 

those making decisions on individual projects or setting standards. A brief summary follows, and 

the implementation guides and fact sheets can be reviewed for further details regarding bicycle 

accommodation, noise issues, and pavement issues. 

• Bicycle accommodation: Agency systematic policies are generally based on providing 

an adequate clear shoulder width between the outside edge of the rumble strip and the 

edge of pavement. Bicyclists have a variety of basic requirements that need to be 

accommodated on shared roadways with vehicles. Additional factors that affect 

bicyclists on roadways with rumble strips are clean pavements and the ability to cross 

rumble strips safety. Agencies should work with the bicycle community to understand 

their needs, to develop policies or solutions that accommodate bicycles and increase 

safety, and to identify higher and lower priority corridors for bicycles. Technical 

specialists making decisions on individual projects or setting standards can find more 

information in the Rumble Strip Implementation Guide: Addressing Bicycle Issues on 

Two-Lane Roads.

(13) Additional information can be found in the FHWA Technical 

Advisory on Shoulder and Edge Line Rumble Strips. 

(14)

• Noise issues: Most agencies address the consideration of potential noise issues in a 

general sense (i.e., acknowledging the possibility). Few States have specific policies 

regarding installation proximity to dwellings and businesses. Technical specialists making 

decisions on individual projects or setting standards can find more information about 

noise accommodation in the Rumble Strip Implementation Guide: Addressing Noise

Issues on Two-Lane Roads.

(15) Additional information can be found in the FHWA 

Technical Advisory on Shoulder and Edge Line Rumble Strips and in the FHWA 

Technical Advisory on Center Line Rumble Strips.

(14)

• Pavement issues: Pavement considerations typically include current pavement 

condition, pavement depth, time to future surface overlay, and location of the rumble 

strip in relation to longitudinal joints. Little connection has been found between 

pavement condition at the time of installation and increased pavement degradation. 

Additionally, preventative maintenance treatments, such as chip seals, ultra-thin hot mix 

asphalt, and micro-surfacing have traditionally been considered to be incompatible with 

rumble strip installations. Recent experiences have shown that these worries may be 

unfounded. Technical specialists making decisions on individual projects or setting 
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standards can find more information in the Rumble Strip Implementation Guide: 

Addressing Pavement Issues on Two-Lane Roads.

(17) Additional information can be found 

in the FHWA Technical Advisory on Shoulder and Edge Line Rumble Strips and in the 

FHWA Technical Advisory on Center Line Rumble Strips.

(14)

Agencies use several different cross-section and rumble strip designs based on these special 

considerations including the following: 

• Different rumble strip configuration. 

• Different rumble strip placement. For example, moving SRS under the pavement 

marking to create an edge line rumble strip. The goal is to maintain a four-foot clear 

space, if possible. The goal is generally five feet if curb or guardrail is present. 

• Consider omitting rumble strips at locations with guardrail and/or curbing if adequate 

clear space cannot be maintained. 

• Reduce the depth of the rumble strip to 3/8 in. 

• Changing lane configurations. For example, narrowing the travel lane to accommodate a 

wider shoulder. 

• Widening the shoulder to accommodate rumble strips and clear space for bicyclists. 

• Utilizing raised rumble strips. 

• Terminating rumble strips in residential areas or providing breaks near residences (as 

necessary). 

If accommodations cannot be made, alternative safety strategies may be considered and 

implemented, if justified. However, alternative strategies may not focus on distracted or drowsy 

driving, which are targeted by rumble strips. For example, agencies may elect to enhance 

delineation as an alternative to rumble strips, in noise sensitive areas (e.g., curve signing, 

delineators, raised pavement markings [RPMs]). Potential alternatives to rumble strips include 

the following: 

• Improving horizontal curve delineation by: 

o Installing or upgrading advance warning signs. 

o Installing advisory speed plaques. 

o Installing Chevrons or a Large Arrow plaque. 

o Installing delineators and/or raised pavement markers. 

o Installing wider pavement markings. 

• Applying high friction surface treatments. 
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Additional alternatives for horizontal curves can be found in the Low-Cost Treatments for 

Horizontal Curve Safety 2016.

(8) The CMF Clearinghouse and the HSM Part D can be consulted 

to determine the potential safety effectiveness of alternative options. 
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OVERVIEW OF CURRENT AND SUCCESSFUL INSTALLATION 

PRACTICES 

Nearly all State agencies have a systematic policy providing standard drawings for CLRS and SRS 

on rural, two-lane, undivided highways or multilane, divided highways. Few agencies use 

different rumble strip designs for the outside shoulder for the two facility types. Most agencies 

that distinguish between the two facility types provide drawings specifying rumble strips on the 

inside and outside shoulders on multilane divided highways. Nearly all agencies supplement the 

systematic approach with a high crash corridor approach for roadways that do not meet 

systematic policy. This flexibility is important because roadways with the highest risk for ROR 

crashes (i.e., roadways with narrow lane and shoulder widths) often do not meet the criteria 

for systematic policies. Flexibility is also important for modifying standard designs to 

accommodate both their installation and the needs of those affected by their presence. This 

section provides an overview of current agency systematic policies and successful high crash 

corridor installation practices. 

CURRENT SYSTEMATIC POLICIES 

Agencies use systematic policies to develop a set of criteria that, if met, automatically qualify 

corridors for rumble strip installation. Systematic policies most often apply to new 

construction, reconstruction, or resurfacing. This work is performed while the contractor is 

already on-site performing other activities and ensures the pavement is in good condition and 

will not be resurfaced again in the near term. Alternatively, agencies install rumble strips as a 

retrofit if the pavement quality is sufficient and there is no scheduled paving activity in the near 

term (the length of time varies by agency). 

Systematic policies provide criteria for installation and a standard specification for rumble strip 

dimension and layout. Criteria for installation are generally not crash or risk-based; they are 

based on roadway geometry, roadway users, and traffic operations. The written policy specifies 

minimum (or maximum) values for which rumble strips may be considered. The SRS and CLRS 

sections provide examples of criteria agencies use for systematic policies. Standard drawings 

provide details on basic rumble strip dimensions, locations, and breaks. Rumble strips are 

typically broken for intersections and bridges; standard drawings may provide details on where 

the breaks occur and may address non-standard applications at locations such as tapers, 

auxiliary lanes, and driveways (if necessary). Additionally, the standard drawing may provide 

information on bicycle gaps. 

Agencies have found increased buy-in for rumble strips when stakeholders are included in 

developing the language for systematic policies. For example, the Montana Department of 

Transportation engaged the bicycle community in developing their policy and received feedback 

on language such as “The ideal clear space between the shoulder rumble strip and the edge of 
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the paved shoulder is 4 ft.”(18) The Montana Department of Transportation has modified the 

design to allow for bicycles and has used quality control to try to ensure that the 4-foot space 

is maintained. Engaging stakeholders also increases buy-in and leads to better solutions for high 

crash corridor solutions when the corridor does not meet the criteria for systematic 

installation. If stakeholders feel that their voice is heard, they will be more open to 

understanding the effectiveness of rumble strips and will be more willing to work toward a 

solution that includes more system-wide installation, even on roadways with bicycle activity. 

The next two sections provide an overview of systematic installation policies and standards for 

SRS and CLRS, respectively. These sections highlight the variability in current practices and the 

practices of the agencies that have been more successful in obtaining buy-in for rumble strip 

installation for non-freeway applications. The discussion focuses on rural, two-lane highways 

and applies to multilane highways. 

Shoulder and Edge Line Rumble Strips 

Table 1 provides an overview of SRS and ELRS design dimensions and systematic installation 

criteria. Note that offset dimensions show the maximum under the agency’s policy. The offset is 

zero for ELRS. The following installation criteria are commonly used by agencies (note blank 

cells indicate no policy specifically dealing with that particular criterion): 

• Minimum posted speed limit. The minimum posted speed limit typically serves as a 

surrogate for level of urbanization. Rumble strips are used in rural areas and are 

typically avoided in urban areas, unless justified by crash history, due to noise 

complaints. 

• Shoulder width. The minimum width is most commonly specified to allow for adequate 

room for bicycle activity; however, several agencies provide rumble strips on narrower 

shoulders due to increased risk for severe crashes, while other agencies do not specify a 

minimum shoulder width.

• Minimum distance to nearby residences. Few agencies specify a minimum distance to 

nearby residences, but for those that do, the distance is most commonly near 650 ft.

• Asphalt condition. There are several criteria used for asphalt condition:

• Structural condition. Several agencies look for the asphalt condition to be “good.” 

• Maximum pavement age. In addition to new pavements, several agencies utilize 

pavement age as a criterion in lieu of structural condition.

• Minimum pavement depth. Several agencies note a minimum depth for the surface coat 

that allows for rumble strip installation within the surface.
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• ELRS option. This column shows agencies that have policies specifying the use of ELRS. 

In the case of those marked N (no), their policy did not directly address the possibility 

of combining the SRS and edge line marking, or their policy only indicated a SRS with a 

specified offset distance from the edge line marking or pavement joint. 

Other installation criteria not shown below include the following: 

• Minimum AADT. Few State agencies specific a minimum AADT threshold for 

installation. Minimum AADT thresholds range from 400 to 3,000 vehicles per day.

• Minimum pavement width. Several states specify SRS or ELRS in lieu of CLRS if the 

pavement width is below a certain value. 

• Minimum distance to residences. A few states have a minimum distance to nearby 

residences. Specified distances range from 100 ft to 2,000 ft. The distance is most 

commonly about 650 ft. 

Figure 7 provides an overview of the dimensions used in Table 1. The dimensions are consistent 

with those provided in the Key Definitions section.

Figure 7. Illustration. SRS rumble strip dimensions.

(6)
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Table 1. Agency systemic SRS installation criteria.

State

A† B† C† D† E

† Bike Gap

Run (ft) 

Bike Gap 

Gap (ft) 

Posted 

Speed (mph)

SW** 

(ft)

Asph

Condi

AL

—

8-12

—

—

—

—

— 45

2 Goo

AK

4 16

7

1⁄2 12 68 12 50

6 Good, >

AZ 10

6-12

7 3

8

 12 30 10

— 5 Avoid 

AR

4

6-16 5 3

8

 12 48 12 50 5 1⁄4 Goo

CA

6

6-12 5 5 16

 14

—

— 40 5 1⁄2 

—

CO

— 12

7 3

8

 12 48 12

— 5 —

CT*

6 16

7

1⁄2 12

—

—

—

—

—

DE

6

6

7 3

8

 12 40 12 40 5 New

FL* 12 16

7

1⁄2 12

—

—

—

—

—

GA 12

6-16

7

1⁄2 12 28 12 55

4

—

HI

2

6-12 5 3

8

 12 47 13 40

4

—

ID 12

6-16

6-7 3

8

 12 48 12

—

2 Goo

IL

—

8-16

7 7 16

 12 48 12

—

—

—

IN

— 16

7

1⁄2 12 50 10

—

—

—

IA

6 12

7

1⁄2 12 48 12 50

4

—

KS

— 12

7

1⁄2 12

—

—

—

2 New, >

KY 12

8-16

7 3

8

 12 50 10 50 1 —

LA

—

6-12

7

1⁄2 14 40 10 50

— Avoid 

ME

6 16

7

1⁄2 12 48 12 45

4 <5 years, 

MD 12

6-12 5-7 3

8

 12 48 12 40 5 Goo

MA

4 16

6 3

8

 12 64 16 40

8

—

MI 12 12

7 3

8

 12 48 12 55

6

—

MN

4

8-12

7 3

8

 12 48 12 55 <4

—

MS

— 12

7 3

8

 12

—

—

—

2

—

MO

— 12

7 7 16

 12

—

— 50

2 >1.75 

MT

6

6-12

7-8

1⁄2 12 47 13 50

4

—

NE

—

8-16

6 5

8

 12

—

— 50

2 Good, >
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State

A† B† C† D† E

† Bike Gap

Run (ft) 

Bike Gap 

Gap (ft) 

Posted 

Speed (mph)

SW** 

(ft)

Asph

Condi

NV

— 5-16

7

1⁄2 12 48 12

—

4

—

NH

— 12

8

1⁄2 12 48 12 40 5 —

NJ*

4 16

7

1⁄2 12

—

—

—

6 >4 i

NM 16 12

7

1⁄2 12 48 12

— <6 Goo

NY 12 12 5-7 3

8

 24 48 12 50

6 Good, >

NC

6

8-16

7

1⁄2 12 30/50 6/12

—

4

—

ND

6

6-12

7

1⁄2 12 40 10 50 <2

—

OH 10

6-16 5-7 3

8

 12 48 12 50

2 PCR>

OK 12 16

7

1⁄2 12 50 10 50

4

—

OR 12

6-16

7 3

8

 12 30 10

—

—

—

PA

4

6-16 5 3

8

 11 48 12 <55

4 Goo

RI

4 12-16

7

—

— 48 12 40

6 New, <5 

SC

—

4-12

7 3

8

 12 48 12 45 <1 Goo

SD

6

8-12

7

1⁄2 12 40 12 50

4

—

TN

—

4-16 5 7 16

 12 60 15 40

0 >1.5 

TX

4

8-16

7

1⁄2 12 40/60 10/12 50 <2 <3 years 

UT 12

6 5 5 16

 12 48 12

— 1 —

VT

—

—

—

—

—

—

—

—

—

—

VA

6 12

7

1⁄2 12 48/52 12/16 45

4 >2 i

WA

6 12-16 5 3

8

 12 28/48 12 45

4 Goo

WV

6 12-16

7 3

8

 12 48 12 45

4

—

WI

6

8

7

1⁄2 12 48 12 55 3 Goo

WY 12 12-16

7 3

8

 12 48 12 50

2

—

Fed Land 12

8 5 1⁄2 12 48 12

—

— Good, >

*Policy and criteria are not specific to rural, two-lane highways. Standards developed for freeways.**Agencies requiring a four-foot shoulder typically require five feet if barrier or curb is present. †A, B, C, D, and E represent dimensions depicted in Figure 7. 

“—” Blank cells indicate no information was available. Posted speed limit and shoulder width are minimum values. 
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Table 1 also provides the standard dimensions and bicycle gaps agency use in practice. Agency 

practices vary most in the length dimension used for rumble strips. Two surveyed agencies have 

a standard 4-inch rumble strip application while many agencies have a minimum standard of 12 

inches or more. Two agencies had policies that were not specific to non-freeway applications 

and one agency had no standard drawings or referenced dimensions. There is also wide variety 

in the run length for bicycle accommodation, although most agencies apply a 10- to 12-foot gap 

for bicycle crossing. 

Many of the agencies listed have one design pattern for all installations and have no flexibility 

built into the policy. Other agencies have built-in flexibility. The flexibility is most commonly 

specifying rumble strip length and offset based on shoulder width. For example, Tennessee 

standards include rumble strip length from 4 to 16 inches and offset ranging from edge line to 

12 inches. The dimension and location of the rumble strip varies based on the available 

shoulder width. For available paved shoulder widths 8 feet or greater, rumble strips are 16 

inches with a 12-inch offset. For available paved shoulder widths of 2 to 8 feet, rumble strips 

are 8 inches and ELRS are specified. For shoulders less than 2 feet, a 4-inch ELRS is specified. 

Many agencies allow for variable rumble strip length and offset to maximize the clearance (allow 

for 4-foot shoulder). 

Flexibility should be built into the policy. Flexibility is important in policy, especially if the policy 

specifies parties that are involved in the decision-making process. For example, the Minnesota 

Department of Transportation (MnDOT) policy provides districts discretion for lateral 

placement to abate noise concerns and accommodate bicyclists.(19) Additionally, the policy 

provides flexibility in rumble strip length based on pavement width, flexibility in offset to 

accommodate bicyclists with input from the State Bicycle Coordinator, and flexibility to gap 

rumble strips on the inside of horizontal curves with nearby residences if a Safety Edge® or 

wider shoulder is installed. 

Center Line Rumble Strips 

Table 2 provides an overview of CLRS design dimensions and systematic installation criteria. 

Note that the spacing is listed as 12/24 inches for several agencies. This indicates that the 

spacing is 12 inches between rumbles followed by a 24-inch gap. The following installation 

criteria are commonly used by agencies: 

• Minimum posted speed limit. The minimum posted speed limit typically serves as a 

surrogate for level of urbanization. Rumble strips are used in rural areas and are avoided 

in urban areas, unless justified by crash history, due to noise complaints. 

• Minimum pavement, lane, or shoulder width. 
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• Minimum distance to nearby residences. Few agencies specify a minimum distance to 

nearby residences, but the distance is most commonly near 650 ft.

• Asphalt condition. There are several criteria used for asphalt condition:

o Structural condition. Several agencies look for the asphalt condition to be 

“good.” 

o Maximum pavement age. In addition to new pavements, several agencies utilize 

pavement age as a criterion in lieu of structural condition.

o Minimum pavement depth. Several agencies note a minimum depth for the 

surface coat that allows for rumble strip installation within the surface.

• Passing zone option. Fifty percent of the agencies surveyed had no specific policy 

regarding CLRS and passing zones. Of those agencies with policies, 22 out of 25 indicate 

that rumble strips should continue through passing zones. Note that one of the three 

agencies specifying CLRS be discontinued in passing zones is reviewing its policy to allow 

CLRS installation in passing zones. A recent study in Minnesota reviewed all two-lane 

fatal head-on crashes and found that passing is rarely a contributing factor.(5) Based on 

this finding, breaking at passing zones would be counter-productive. 

Other installation criteria not shown below include: 

• Minimum AADT. Few State agencies specify a minimum AADT threshold for installation. 

Minimum AADT thresholds range from 1,500 to 3,000 vehicles per day.

• Shoulder width. Few States have a minimum shoulder width requirement; however, 

some States use the minimum shoulder width to specify whether edge line rumble strips 

may be used in place of CLRS. 

• Minimum distance to residences. A few states have a minimum distance to nearby 

residences. Specified distances range from 100 feet to 2,000 feet. The distance is most 

commonly about 650 feet. 

Figure 8 provides an overview of the dimensions used in Table 2. The dimensions are consistent 

with those provided in the Key Definitions section.
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Figure 8. Illustration. CLRS rumble strip dimensions.(6)

As with SRS, the length dimension varies most for CLRS among agency practices. The most 

common applications are 12 and 16 inches, but range from 8 to 20 total inches. Several agencies 

use two rumble strips, straddling the center line joint; however, most agencies mill one rumble 

strip centered on the joint. Agencies also differ in spacing for CLRS. SRS are nearly universally 

spaced 12 inches center-to-center, whereas CLRS are sometimes spaced 12 inches, or 12 

inches and then 24 inches. Agencies do this to differentiate the noise and vibration between 

CLRS and SRS. The intention is to alert drivers to which direction they have drifted in order to 

maneuver in the appropriate direction. 

There is less flexibility in rumble strip length for CLRS than for SRS; however, it is important 

that systematic policies address flexibility for noise mitigation and design standards address 

rumble strip placement with respect to RPMs. 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STR

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Table 2. Agency systematic center line rumble strip installation criteria. 

State

B† C† D† E

† Min Width 

–

Pave (ft) 

Min Width 

–

Lane (ft) 

Posted 

Speed (mph)

Aspha

Condit

AL

8-12

—

—

—

— 11

— Good

AK 12

7

3

8

 12 28

— 45 Good, >2 

AZ

6

7

3

8

 12

— 11 45

—

AR 16 5

3

8

 12 28 10 45 Good

CA

6-12 5

5

8

 12

—

— 40

—

CO 12

7

3

8

 12

—

—

—

—

CT 12

7

3

8

 24 26

— 40 Good

DE 16

7

3

8

 12

— 10 40 New

FL

—

—

—

—

—

—

—

—

GA 16

7

1⁄2 12

—

—

—

—

HI 16-20

6-9

1⁄2 12

—

— 40

—

ID 12

7

1⁄2 12 24

—

— Good 

IL

—

—

—

—

—

—

—

—

IN 16

7

1⁄2 12/24

—

—

—

—

IA 16

7

1⁄2 12/24

— 11 50 <5 yea

KS 12

7

1⁄2 12

—

—

— New, >1.

KY

8-12

7

3

8

 12

— 11 50

—

LA

6-12

7

1⁄2 14 24 11 50 Avoid jo

ME 12

7

1⁄2 24

— 11 45 <5 years, >

MD 16

7

1⁄2 24/36

— 10 40 Good

MA

—

—

—

—

—

—

—

—

MI 16

7

3

8

 12/24 26

— 55

—

MN 16

7

3

8

 12

— 11 55

—

MS

—

—

—

—

—

—

—

—

MO 12

7

7

16

 12/24

— 10 50 >1.75 i

MT

6-12

7-8

1⁄2 12/24

—

— 50

—

NE

—

—

—

—

— 11 50 Good, >2
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STR

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State

B† C† D† E

† Min Width 

–

Pave (ft) 

Min Width 

–

Lane (ft) 

Posted 

Speed (mph)

Aspha

Condit

NV 12

7

1⁄2 12

—

—

—

—

NH 12

7

1⁄2 12 28

— 40 Good, >1.

NJ 16

7

1⁄2 12

— 10 35 Good, SD

NM 16

7

1⁄2 12/24 26 12 50 Good

NY 12

7

3

8

 24 26

— 45 Good, >0

NC

—

—

—

—

—

—

—

—

ND

6-12

7

1⁄2 12/24

—

— 50

—

OH 16 5

3

8

 12/24

—

—

—

—

OK

—

—

—

—

—

—

—

—

OR 16

7

1⁄2 24/48

—

—

—

—

PA 14-18

7

1⁄2 24/48

— 10

— Good, >2

RI 12

7

— 12

— 11 40 New, <5 y

SC 12

7

3

8

 14

— 10 45 Good

SD 12 5

3

8

 12

—

— 50

—

TN 12

7

7

16

 24

— 12 40 Avoid jo

TX 16

7

1⁄2 24

— 11 50 <3 years >

UT

6

8

5

8

 12

—

—

—

—

VT 12-18

7

3

8

 12/24 28

— 45 Good

VA 14

7

1⁄2 12

— 11 45 >4 in

WA 12

7

1⁄2 12 24

—

— Good

WV

—

—

—

—

— 11 45

—

WI

8

7

3

8

 12/24

— 12 55 Good

WY 12

7

1⁄2 12

—

— 50

—

*Policy being reviewed currently. Note that blank rows indicate no policy indicated.†A, B, C, D, and E represent dimensions depicted in Figure 8. 

“—” Blank cells indicate no information was available. Posted speed limit, pavement, and lane width are minimum 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

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SUCCESSFUL HIGH CRASH CORRIDOR INSTALLATION PRACTICES 

Many high-risk locations may not qualify for systematic installation but may benefit from rumble 

strip installation based on crash history. Highway corridors, with narrow shoulders for 

example, may not provide adequate clear space for bicyclists with rumble strip implementation 

but may have a history of high ROR crash counts. Practitioners can use the methods provided 

in the Rumble Strips and Safety Management section to identify the need for and potential 

benefits of rumble strips in these corridors. Most agencies reviewed do not provide specific 

guidelines for how and when to install rumble strips in these cases. Additionally, these corridors 

will have the greatest potential for installation issues due to special considerations. 

Consideration of the potential benefits and trade-offs is paramount, and the agencies with the 

most success installing rumble strips have written processes or requirements, including who is 

involved in the final decision-making. Successful policies include relevant stakeholders in the 

decision-making process once identifying the need. 

Several agencies identify key personnel involved with decision-making or identify personnel who 

are typically included in a rumble strip decision-making committee. Examples of personnel who 

may be involved in the decision-making process include the following (note that agencies differ 

in the titles of individuals and names of key offices): 

• Designers. 

• Traffic engineers. 

• Safety analysts. 

• Bicycle or non-motorized coordinators. 

• Environmental engineers. 

• Planners. 

• Maintenance personnel. 

Each of these personnel may be considered at the local/county, regional/district, or 

State/central office level of the organization and concurrence among personnel is paramount. 

Additionally, stakeholders may be included in the process or notified as early as possible to 

allow time for feedback. Potential stakeholders include municipalities, local bicycle groups, and 

adjacent roadway property owners and residents. Their feedback is critical, and should be 

considered in combination with potential safety benefits. This also provides the agency an 

opportunity to provide stakeholders with information on the safety benefits, including specific 

performance measures calculated in the safety analyses. This may help the agency to promote 

rumble strips to stakeholders. 
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A few agencies also note the importance of project decision documentation. Due to the 

potential safety impact of decisions, it is important to document the need and the decision 

whether or not to install rumble strips, and why. Documentation is also important for 

explaining the benefits to stakeholders and to those who may perceive a disbenefit to their 

installation. The Texas Department of Transportation (TxDOT) noted that if they demonstrate 

the historical crash reduction factors for rumble strip installations to the general public they 

have fewer complaints after installation. 

The Montana Department of Transportation has a specific process for new construction, 

reconstruction, rehabilitation, and overlay corridors where the shoulder width is greater than 1 

foot but less than 4 feet. The procedure includes the following steps:(18) 

1. Complete an economic analysis targeting roadway departure crashes to determine if 

rumble strips are justified. 

2. The Planning Division determines if and how bicyclists use the highway corridor using 

bicycle route maps, bicycle use heat maps, or other methods. 

3. If rumble strips are justified and the roadway is determined to be a high priority bicycle 

route, then a Rumble Strip Committee meeting is convened by the Project Design 

Manager. The committee evaluates the route and recommends and documents the 

appropriate action in the appropriate report (such as the scope of work report). The 

members of the committee include members from the Traffic and Safety Bureau, 

Planning Division, Highways Bureau, and the District. Other divisions are included on an 

as-needed basis. 
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MODEL DECISION-SUPPORT FRAMEWORK FOR RUMBLE STRIP 

INSTALLATION 

OVERVIEW OF MODEL DECISION-MAKING PROCESS 

Agencies that have successfully installed CLRS and SRS on their rural, two-lane and multilane 

systems generally have formalized processes for systematic installation and for decision-making 

on corridors that do not meet systematic criteria. It is important to identify corridors that can 

actually benefit from the treatment and to apply the most effective treatment possible, while 

considering other roadway users and contexts. This section outlines general model guidance for 

steps that may be included in a decision-making process, factors to consider, and who may be 

involved in such a process. Figure 9 provides an overview of the model decision-making 

framework, which is based on a detailed review of current agency practices across the country. 

The framework is not intended to be directly applicable to every agency as regulations, policies, 

practices, and organizational structure can vary across States. The framework offers a 

structured approach for increasing consistency and the chance of success in installing rumble 

strips to achieve safety benefits, while providing a context sensitive approach to reduce the 

impacts on non-motorists. 

This model framework is based on an analysis due to systematic installation (e.g., the roadway is 

being repaved and did not previously have rumble strips). Corridors may also be identified 

based on crash data analysis and rumble strips may be selected as a candidate treatment. In this 

case, the installation has already been justified based on crash data and the analyst would begin 

at Step 3 of the decision-making process presented in Figure 9. There are additional methods 

for project identification and it is up to the analyst to determine which step to begin with in the 

process. 

Explanation of Model Decision-Making Process 

This section describes the decision-making process shown in Figure 9. Each decision-point is yes 

or no after careful consideration by the appropriate parties. Each step includes an overview of 

the questions or trade-offs that may be considered, the parties involved, and what information 

is necessary for decision-making. The final decisions include installing standard rumble strips, 

installing modified rumble strips, installing alternate treatments, or no installation. 
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Figure 9. Illustration. Model decision-making framework for rumble strip 

installation. 

Step 1. Systematic Installation 

This step identifies whether or not a corridor is a candidate for installation based on systematic 

policy. This step typically involves the designer or design team and necessitates information on 

roadway attributes and operations attributes and generally coincides with resurfacing, 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

43

rehabilitation, or new construction. If the corridor meets the policy criteria and the policy 

explicitly considers bicyclists, external noise, and pavement condition, then the standard design 

can be installed. If the policy does not include these special considerations, then they are 

addressed in Step 3 (and Step 2 can be skipped). If the corridor does not meet the criteria for 

systematic installation, then move forward to Step 2. 

Step 2. Systemic and High Crash Corridor Installation

This step identifies the need for rumble strip installation based on the methods provided in the 

Rumble Strips and Safety Management section. Although the corridor does not qualify for 

systematic installation, the corridor may benefit from rumble strip installation. Agencies may 

consider using a systemic (i.e., risk-based) approach and a high crash corridor approach. 

In the systemic approach, analysts identify corridors based on a combination of risk factors, 

rather than crash history. Crash history can be combined with CMFs for candidate 

countermeasures in order to determine the potential crash reduction and cost-effectiveness of 

the proposed measure(s). The systemic approach typically focuses on fatal and severe injury 

crashes, which are not normally clustered, but provide an opportunity for cost-effective 

widespread implementation. 

In the high crash corridor approach, staff use historical (observed) crashes, expected crashes, 

predicted crashes, or some combination thereof to identify the need for mitigation. As noted in 

the High Crash Corridor Safety Approach section, the preferred methods use predicted 

crashes or expected crashes in the selection of high crash corridors. Once potential mitigation 

measures are identified, staff apply CMFs in order to determine the potential crash reduction 

and cost effectiveness of the proposed measures. 

In this step, the designer may need to consult with traffic engineers or safety engineers/analysts 

to develop the justification for installation. If the corridor does not warrant installation, then 

the decision will be for no installation. If the corridor does warrant installation, then the 

designer or analyst would document the need and potential safety benefit and move forward to 

Step 3. 

Step 3. Special Considerations 

There are three special considerations within this step: pavement condition, bicycle 

accommodation, and noise accommodation. Each of these are discussed individually. 
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Step 3a: Pavement Condition 

The pavement should be in good condition (i.e., minimal cracking) and have adequate pavement 

depth when rumble strips are installed. There is little evidence showing accelerated degradation 

due to rumble strip installation, but agencies have noted accelerated degradation when the 

pavement surface was in poor condition. Maintenance personnel may be involved in the 

decision-making process if the pavement quality is in question, or a pavement quality database 

can be consulted. If the installation is part of a pavement resurfacing, rehabilitation, or a new 

construction, then pavement condition is not a concern. Refer to the FHWA Rumble Strip 

Implementation Guide: Addressing Pavement Issues on Two-Lane Roads for more details on 

pavement issues.(17) If the pavement condition is adequate or a major reconstruction is more 

than 3 to 5 years away, then move forward to Step 3b. If the pavement condition does not 

support installation, then move forward to Step 5. 

Step 3b: Bicycle Accommodation 

If bicyclists are not considered in the development of the standard rumble strip design, there 

are likely to be modifications needed for some installations. Bicyclists have difficulty traversing 

rumble strips and need adequate clear space on the shoulder and periodic breaks to cross over 

rumble strips. A non-motorized transportation coordinator (typically the bicycle and pedestrian 

coordinator) and local stakeholders are consulted to determine if 1) the corridor is a 

designated bicycle route or 2) if bicyclists utilize the corridor. This consultation utilizes maps of 

designated bicycle corridors, crowdsourcing technology that identifies bicycle usage, or 

discussion with those who have local knowledge. Refer to the FHWA Rumble Strip 

Implementation Guide: Addressing Bicycle Issues on Two-Lane Roads for more details on 

bicycles issues and accommodation.(13) If it is determined that bicycles use the route, and the 

standard installation will result in inadequate clear space, then move forward to Step 4. If 

bicycle accommodation is not a concern, then move forward to Step 3c. 

Step 3c: Noise Accommodation 

If noise accommodation is not considered in the development of the standard rumble strip 

design, there are likely to be modifications needed for some installations. Vehicles traversing 

over rumble strips result in noise that differs from background highway noise, which can disturb 

nearby residents. An environmental specialist with a background in noise can be consulted to 

determine if noise is a potential concern for this installation. Refer to the FHWA Rumble Strip 

Implementation Guide: Addressing Noise Issues on Two-Lane Roads for more details on noise 

issues and accommodation.(15) The number of receptors, locations of residences, traffic volume, 

and traffic characteristics are of interest where your agency has no formal policy on noise 

mitigation. This work utilizes plan-view mapping, site visits, discussion with residents, or 

discussion with those who have local knowledge. If it is determined that noise accommodation 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

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is necessary, then move forward to Step 4. If noise accommodation and bicycle accommodation 

is not a concern, then the standard rumble strip design may be installed. 

Step 4: Alternative Rumble Strip Designs for Accommodating Bicycles and/or Noise 

Step 4 applies to corridors identified to have bicycle accommodation and/or noise 

accommodation concerns and roadway elements do not allow for standard installations (e.g., 

shoulder width too narrow to allow for bicycle clear space). In this step, a rumble strip 

committee may be consulted to come to a consensus about rumble strip installation and to 

determine any potential changes to the standard design. The rumble strip committee may 

include a roadway designer, a non-motorized coordinator, a noise specialist, a traffic or safety 

engineer/analyst, and an individual from maintenance. At this point, the rumble strip committee 

can consult with outside stakeholders (e.g., local stakeholders) to weigh the potential safety 

benefits versus the special considerations. The rumble strip committee will consider the 

installation of the standard design, potential modifications (e.g., those listed in the Special 

Considerations section), or not installing rumble strips. Modifications to the design, such as a 

shallower rumble strip or sinusoidal pattern, may provide adequate warning for motor vehicles 

and accommodate bicycle and noise concerns. If the committee determines there are too few 

safety benefits, which do not outweigh other concerns, then move forward to Step 5, 

otherwise install the recommended design (standard or modified). 

Step 5: Alternative Treatments 

If the analyst determines rumble strips are not a viable solution in Step 3a or Step 4, and there 

is a documented safety problem, then the analyst may consider alternative treatments. The 

Special Considerations section presents a short list of alternatives for consideration; however, 

other treatments may not focus on distracted or drowsy driving. The CMF Clearinghouse 

(www.cmfclearinghouse.org), HSM Part D, the Low-Cost Treatments for Horizontal Curve 

Safety 2016 guide, and the NCHRP Report 500: Guidance for Implementation of the AASHTO 

Strategic Highway Safety Plan series may be consulted for additional potential countermeasures. 

Alternative strategies may be considered based on their effectiveness in reducing the crash type 

or types of interest. The final decision should be documented along with the expected safety 

benefit. The rumble strip committee may be involved in the decision-making or the designer can 

consult with traffic engineering or safety analysts. If no viable alternatives are identified, then the 

committee or individual may recommend not to install any countermeasures. In this case, the 

decision should also be documented. 
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CASE STUDIES 

This section includes case study examples where agencies weighed the decision to install CLRS 

or SRS when there was potential concern for roadway users other than vehicles, nearby 

residents, and pavement condition. Examples include cases where rumble strips were installed 

and later removed after working with local residents as well as an economic analysis of systemic 

rumble strip installation. These examples show the importance of involving local residents, 

advocacy groups, and rumble strip committees in policy-making and implementation decisionmaking. Case studies were provided by Michigan Department of Transportation (MDOT), 

MnDOT, and TxDOT. 

RUMBLE STRIP CASE STUDY FROM MICHIGAN 

Accommodating Amish in Rumble Strip Policy 

Michigan policy indicates that non-freeway SRS should be used on all rural, two-lane, four-lane, 

and divided trunk lines where the posted speed limit is 55 miles per hour and the paved 

shoulder is at least 6 feet wide. If safety concerns outweigh other issues, such as noise and 

bicycle use, non-freeway SRS can be installed on roadways with narrower shoulders. Early on in 

the expansion of MDOT’s non-freeway rumble strip program (around 2008), MDOT was made 

aware of concerns from the Amish community in the southwestern part of the State regarding 

SRS and the effect on their buggies and horses. The horses would not cross the rumble strips, 

both CLRS and ELRS. As mitigation, when calling for SRS, designers tried placing the rumble 

strips very close to the edge line rather than the standard 12-inch offset to leave more room 

between the rumbles and the edge of the paved shoulder. However, the Amish did not like the 

resulting tight squeeze and used the travel lane. When a vehicle would pass them, they would 

cross the CLRS, scaring the horses. Along the same line, the horses did not like to cross the 

rumble strips because the rumble strips made it difficult for them to set their feet down. There 

was at least one instance of a horse getting hurt because of stepping into the rumble strips. 

As a result of these issues, several sections of non-freeway rumble strips were filled-in to 

accommodate the horses and buggies. Additionally, rumble strips were omitted in some areas 

for which they were planned. Within a few months of the concerns being raised, MDOT’s 

design guidance was modified to take these unique road users into account. The guidance now 

indicates that “in locations where horse-drawn buggies utilize the roadway, do not use shoulder 

corrugations unless a crash history exists. Document this as a context sensitive design decision. 

When a correctable crash history does exist, consider using corrugations and widening the 

shoulder 2 ft to accommodate both.” 
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Accommodating Pavement Preservation in Rumble Strip Policy 

The expanding use of rumble strips has resulted in changes to how Michigan roadways are 

constructed and maintained. Due to concerns that cutting CLRS into an asphalt joint could 

expedite the joint deterioration, the MDOT adopted a joint density specification to ensure the 

center line pavement was sound. A field visit with FHWA representatives determined that a 

single chip seal over rumble strips allowed the rumble strips to maintain functionality; however, 

a double chip seal significantly reduced the effectiveness. MDOT has updated their Special 

Provisions for chip seals to indicate that when performing a double chip seal only the top layer 

crosses the rumble strips. Upon finding that microsurfacing treatments essentially nullified 

rumble strips but still reflected the grooves (which would be hard to line up on for cutting), 

MDOT updated their Special Provision for microsurfacing to indicate rumble strips should be 

filled-in with microsurfacing material prior to the surface treatment such that rumble strips can 

be re-cut afterwards. 

RUMBLE STRIP CASE STUDIES FROM MINNESOTA 

Highway 19 near New Prague 

Near New Prague on Highway 19, MnDOT installed CLRS in 2014 in compliance with the State 

Technical Memorandum. Due to frequent hits of these rumble strips, several residents in the 

vicinity started to send complaints to the District 6 office (located in Rochester, MN). The 

district responded by investigating the highway and working with the residents to identify the 

locations that were generating the noise pollution. After determining which locations, the 

district removed the rumble strips at the identified locations and has since replaced them with 

an experimental sinusoidal rumble strip that should create less nuisance noise. Since installation, 

the district has not received any complaints from the residents. The efforts to remove the 

rumbles and repave the removed areas did consume both time and money by MnDOT 

Maintenance and Engineering sections. MnDOT did have to pay for the rumble strip contractor 

to mobilize and cut in the sinusoidal rumble strips on the one section of roadway. 

Highway 61 in Northern Minnesota 

Along the North Shore in Minnesota, Highway 61 closely follows the shore of Lake Superior. In 

compliance with both the State Technical Memorandum regarding rumble strips, and with the 

State strategic initiatives to apply systemic safety countermeasures, MnDOT’s District 1 

(headquartered in Duluth, MN) installed CLRS along the highway in 2013. Approximately 40 

miles of CLRS were installed north of Grand Marais under a districtwide CLRS project and 9 

miles of CLRS were installed between Two Harbors and Beaver Bay on a mill and overlay 

project. Shortly after the installation, complaints started to be received from residents and 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

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others with lake/vacation homes. The noise created by hitting the rumble strips was creating 

noise pollution that many near the highway found to be unacceptable. After significant outcry 

and organization by the local population (the Cook County Board played a very active role), a 

noise study was conducted to better understand the issue and potential solutions. The noise 

study had some findings that the noise would carry further and with greater amplification then 

was initially assumed. With these findings, District 1 management decided to fill-in or remove 

certain rumble strips that were near residential locations along significant portions of the 

highway. All told, nearly 46 miles (with the exception of approximately 3.5 miles near the 

Canadian Border) of rumble strips were filled in to the satisfaction of area residents. Since the 

removal, very few complaints have been received. The District is looking into the idea of using 

sinusoidal rumble strips as a potential countermeasure on any future projects. This project 

helped jump start a MnDOT initiative to find a quiet yet effective rumble strip. As of the 

summer of 2016, MnDOT has approved a sinusoidal rumble strip that provides internal 

vibration and acceptable noise levels, while producing very little noticeable external noise. 

Highway 14 from Mankato to Nicollet 

Highway 14 is a major arterial in southern Minnesota, spanning from South Dakota to 

Wisconsin. The highway connects farms to population centers and manufacturing and trade 

hubs, and is considered a part of the Interregional Corridor System. Highway 14 is also a 

combination of designs, including two-lane highway, high-speed expressway, and full freeway 

design. In 2012, near Mankato, a two-lane section of the highway was determined to have a 

statistically significant above-average rate of fatal head-on crashes. As a response to this issue, 

MnDOT agreed to expand the highway to a four-lane expressway. However, this would not be 

completed until the 2016-2017 timeframe. Rather than doing nothing during the project 

initiation and design phases, District 7 (headquartered in Mankato, MN) made the decision to 

try an interim typical section to prevent or reduce the chances of a fatal crossover crash. The 

typical section changed from 10-foot shoulders and 12-foot lanes (total 44-foot width paved 

top) to a typical section of 7-foot shoulder – 11-foot lane – 8-foot buffer (with tube 

delineators) – 11-foot lane – 7-foot shoulder. The buffer was a double striped yellow line with 

rumbles, and was on each side of the delineators (see Figure 10 for an example from Bing 

Streetside). This was completed in October of 2012. The after results, though a small sample 

size, appear to be promising. Before the application, this 7-mile segment was experiencing an 

average of one fatal or severe head-on crash per year, and has only had one minor crossover 

crash since implementation (through 12/31/2015). In the time frame from 2006 to September 

2012 (6.75 years), there were 59 crashes of all types, and from November 2012 through the 

end of 2015 (3 years), there have been 20 crashes, resulting in nearly a 30 percent total crash 

reduction. On the target crash type (head-on, ROR-left, and sideswipe) the corridor has gone 

from 20 crashes in the before period (from 2006 to September 2012 - 6.75 years), to only 4 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

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crashes (from November 2012 to December 2015 – 3 years) after; resulting in a nearly 60 

percent total target crash reduction. Fatal and serious injury crashes have gone from 6 to 0. 

Figure 10. Photograph. Buffer median on Highway 14 from Bing Streetside.(20)

RUMBLE STRIP CASE STUDY FROM TEXAS 

Systemic Installation of Rumble Strips 

Currently (since 1999), TxDOT requires that rumble strips be used for rural, four-lane or 

more divided highways with a speed limit greater than 45 miles per hour. Rumble strips on 

rural, undivided highways are installed based upon a B/C analysis of the crash history at that 

location. The higher the B/C ratio, the more likely they will be installed. 

In 2016, the Texas Traffic Safety Force conducted an economic analysis of installing CLRS and 

ELRS on 20,000 miles of rural undivided highways with adequate pavement width.(21) Assuming 

an average installation cost of 18,000 dollars per mile, the total cost of installations was 

estimated to be 360 million dollars. The CLRS and ELRS installations would target ROR and 

head-on crashes, with an estimated 170 to 180 lives saved per year and 2,800 to 2,900 crashes 

prevented per year. With a conservative estimate of a 5-year service life, the potential lives 

saved over service life was estimated to be 850 to 900 lives. The estimated cumulative benefit 

for was estimated to be 4.3 billion dollars, resulting in a B/C ratio of 12 dollars for every dollar 

spent. 

The task force recommended installing CLRS and ELRS on rural undivided highways with 

adequate lane and shoulder widths. Additionally, further installations were noted to be 

implemented through collaboration between TxDOT districts and the Maintenance and Traffic 

Operations Divisions. 
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OTHER RESOURCES 

The FHWA maintains a Rumble Strips and Rumble Stripes website, which is accessible at 

safety.fhwa.dot.gov/roadway_dept/rumble_strips/. The website contains resources on safety; 

design and construction; accommodating all users; mitigating noise; pavement and maintenance; 

and policies, guidance, and research. The website also contains implementation fact sheets for 

designers and implementation guides for technical specialists focusing on noise, pavements, and 

bicycle accommodation. The FHWA also has technical advisories on Rumble Strips for Shoulder 

and Edge Line Rumble Strips (T 5040.39, Revision 1) and Center Line Rumble Strips (T 

5040.040, Revision 1). 

For more information on rumble strip or alternative countermeasure effectiveness, visit the 

CMF Clearinghouse at www.cmfclearinghouse.org. 

For more information on the HSM, visit www.highwaysafetymanual.org. 
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APPENDIX A—EXAMPLE CMF TABLES 

Appendix A contains CMFs available on the CMF Clearinghouse for CLRS, SRS, and their 

combination in the following tables: 

• Table 3: Sample CMF Clearinghouse CMFs for CLRS on Rural, Two-Lane Highways. 

• Table 4: Sample CMF Clearinghouse CMFs for SRS on Rural, Two-Lane Highways. 

• Table 5: Sample CMF Clearinghouse CMFs for SRS on Rural, Multilane Highways. 

• Table 6: Sample CMF Clearinghouse CMFs for CLRS and SRS on Rural, Two-Lane 

Highways. 

Each table provides 5-star and 4-star CMFs covering a breadth of crash types, crash severity, 

jurisdictions, AADTs, and geometric conditions. The tables report the ID for each CMF, the 

estimated CMF, and the lower and upper 95-percent confidence intervals. These are currently 

the highest quality CMFs available for each installation type. Note the countermeasure name, 

number of lanes and area type are already accounted for in these tables. Also note there is little 

variability in minor factors for each installation type for these CMFs. The CMFs in Table 3, 

Table 4, and Table 6 , apply to rural, two-lane highways and the CMFs in Table 5 apply to rural, 

multilane highways. These CMFs are mainly distinguishable by their applicable crash type and 

crash severity. However, a few CMFs are applicable to specific geometric characteristics as 

noted in the final column of each table. 

The specific characteristics listed in the final column help to identify where the treatment may 

be more effective. For example, Table 6 provides separate CMFs for AADT less than 3,200 and 

AADT greater than or equal to 3,200. While the difference is not statistically different, the 

average CMF for the higher volume is 0.70 versus 0.85 for the lower volume, indicating that 

shoulder and CLRS may be more effective on high-volume roadways. Comparing CMFs 

provides insights into which crash types, severities, and locations the treatment is more 

effective at mitigating. 
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Table 3. Sample CMF Clearinghouse CMFs for CLRS on rural, two-lane highway

ID Stars CMF L95 U95 Crash Type Crash Severity Jurisdiction Min AADT Max AADT 

3350 5 0.91 0.84 0.98 All F & I MN, PA, WA 574 20,7843355 5 0.63 0.53 0.73 Head-on, Sideswipe All MN, PA, WA 574 20,784 3360 5 0.55 0.43 0.68 Head-on, Sideswipe F & I MN, PA, WA 574 20,784 3361 5 0.91 0.87 0.95 All All CA, CO, DE, MD, MN, OR, PA, WA 574 20,784 3362 5 0.88 0.83 0.94 All F & I CA, CO, DE, MD, MN, OR, PA, WA 574 20,784 3363 5 0.7 0.61 0.79 Head-on, Sideswipe All CA, CO, DE, MD, MN, OR, PA, WA 574 20,784 3375 5 0.53 0.34 0.72 Head-on, Sideswipe All MN, PA, WA 574 20,784 3383 5 0.85 0.73 0.97 All F & I MN, PA, WA 574 20,784 3387 5 0.51 0.38 0.65 Head-on, Sideswipe All MN, PA, WA 574 20,784 3367

4 1.04 0.91 1.17 All All MN, PA, WA 574 20,784 

3371

4 0.94 0.78 1.10 All F & I MN, PA, WA 574 20,784 

3379

4 0.92 0.84 1.00 All All MN, PA, WA 574 20,784 

5398

4 0.71 0.52 0.90 Other All KS 200 8,000

5400

4 0.81 0.53 1.08 ROR All KS 200 8,000

7244

4 0.73 0.72 0.73 Target All MI

—

—

7245

4 0.47 0.47 0.47 Target-Wet All MI

—

—

7246

4 0.99 0.98 0.99 Target-Winter All MI

—

—

7247

4 0.57 0.57 0.57 Target-Passing All MI

—

—

7248

4 0.71 0.71 0.72 Target-Impaired All MI

—

—

7250

4 0.68 0.68 0.68 Target A Inj. MI

—

—

7251

4 0.61 0.60 0.61 Target B Inj. MI

—

—

7252

4 0.72 0.72 0.72 Target C Inj. MI

—

—

7253

4 0.84 0.83 0.84 Target PDO MI

—

—

“—” Blank cells indicate no information was available.
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Table 4. Sample CMF Clearinghouse CMFs for SRS on rural, two-lane highways

ID Stars CMF L95 U95 Crash Type Crash Severity Jurisdiction Min AADT Max AADT 

3442 5 0.84 0.68 1.00 ROR All MN, MO, PA 782 10,3863454 5 0.64 0.45 0.83 ROR F & I MN, MO, PA 782 10,3863394 4 0.67 0.43 0.91 ROR F & I MN, MO, PA 180 12,776 3408 4 0.57 0.29 0.86 ROR F & I MN, MO, PA 180 12,776 3418

4 1.06 0.95 1.17 All All MN, MO, PA 782 10,386

3430

4 0.92 0.76 1.08 All F & I MN, MO, PA 782 10,386

3582

4 1.18 0.88 1.48 ROR, wet road All MN, MO, PA 782 10,386

3603

4 0.89 0.64 1.14 ROR, night All MN, MO, PA 782 10,386

3627

4 0.46 0.21 0.71 ROR F & I MN, MO, PA 180 12,776 

3651 4 0.62 0.33 0.91 ROR F & I MN, MO, PA 180 12,776 7255

4 0.67 0.67 0.68 Target All MI

—

—

7256

4 0.44 0.44 0.45 Target-Wet All MI

—

—

7257

4 0.95 0.94 0.96 Target-Winter All MI

—

—

7258

4 0.64 0.64 0.65 Target-Passing All MI

—

—

7259

4 0.60 0.59 0.61 Target-Impaired All MI

—

—

7261

4 0.68 0.67 0.68 Target A Inj. MI

—

—

7262

4 0.46 0.46 0.47 Target B Inj. MI

—

—

7263

4 0.65 0.64 0.66 Target C Inj. MI

—

—

7264

4 0.72 0.71 0.72 Target PDO MI

—

—

“—” Blank cells indicate no information was available.
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Table 5. Sample CMF Clearinghouse CMFs for SRS on rural, multilane highway

ID Stars CMF L95 U95 Crash Type Crash Severity Jurisdiction Min AADT Max AADT 

3414 5 1.18 1.03 1.33 All All MN, MO, PA 4,959 20,7633438 5 1.40 1.16 1.64 ROR All MN, MO, PA 4,959 20,7633450

4 0.97 0.71 1.23 ROR F & I MN, MO, PA 4,959 20,763

3426

4 0.90 0.70 1.10 All F & I MN, MO, PA 4,959 20,763

6649

4 0.76 0.65 0.87 All All FL 2,000 50,000 

6650

4 0.64 0.50 0.79 All F & I FL 2,000 50,000 

6653

4 0.61 0.41 0.82 All All FL 2,000 50,000 

6654

4 0.57 0.30 0.83 All F & I FL 2,000 50,000 

6655

4 0.79 0.67 0.92 All All FL 2,000 50,000 

6653

4 0.66 0.49 0.83 All F & I FL 2,000 50,000 

6665

4 0.61 0.49 0.72 All All FL 2,000 50,000 

6667

4 0.54 0.37 0.71 ROR All FL 2,000 50,000 

6669 4 0.35 0.23 0.47 All All FL 2,000 50,000 6671 4 0.81 0.62 1.00 All All FL 2,000 50,000 4780 4 0.76 0.63 0.89 All F & SI MO 

—

— 

4781 4 0.74 0.67 0.81 All F & I MO 

—

— 

4782 4 0.86 0.77 0.95 All F & I MO 

—

— 

4787 4 0.75 0.51 0.99 All F & I MO 

—

— 

“—” Blank cells indicate no information was available.
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Table 6. Sample CMF Clearinghouse CMFs for CLRS and SRS on rural, two-lane hig

ID Stars CMF L95 U95 Crash Type Crash Severity Jurisdiction Min AADT Max AADT 

6850 5 0.80 0.75 0.85 All All KY, MO, PA 154 25,7966851 5 0.77 0.70 0.84 All F & I KY, MO, PA 154 25,7966852 5 0.74 0.66 0.82 ROR All KY, MO, PA 154 25,7966853 5 0.63 0.47 0.80 Head-on All KY, MO, PA 154 25,7966854 5 0.77 0.58 0.96 Sideswipe All KY, MO, PA 154 26,1186973 5 0.85 0.68 1.03 ROR All KY, MO, PA 154 3,199 6974 5 0.70 0.61 0.79 ROR All KY, MO, PA 3,200 26,118 4790 4 0.62 0.43 0.81 All F & I MO 

—

— 

“—” Blank cells indicate no information was available.
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APPENDIX B—DETAILED EXAMPLE APPLICATIONS 

Example Application 1 – Systemic Installation 

An agency has identified 7,500 miles of rural, two-lane highways for retrofit installation of ELRS. 

The following information was identified for developing a B/C analysis of rumble strip 

implementation. 

Assumptions: 

• ELRS cost per mile: 1,500 dollars per line. 

• Annual fatal and injury ROR crashes: 125 crashes. 

• Rumble strip life expectancy: 7 years. 

• CMF for ELRS for fatal and injury ROR crashes: 0.67. 

o CMF should be for fatal and injury ROR crashes. 

o CMF should be for ELRS if possible, SRS if no information available. 

o Use CMF 3394 from CMF Clearinghouse. 

• 2001 crash cost for fatal and injury crashes: 158,177 dollars. 

Costs: 

• Installation cost = 1,500 dollars × 2 sides of the roadway = 3,000 dollars per mile. 

• Total cost = 3,000 dollars per mile × 7,500 miles = 22,500,000 dollars. 

• Capital Recovery Factor = ((1 + 0.07)7 - 1)/(0.07 × (1 + 0.07)7) = 5.39. 

• Annualized construction cost = 22,500,000/5.389 = 4,174,947 dollars. 

Benefits: 

• Annual fatal and injury ROR crashes saved = 125 crashes × (1 – 0.67) = 41.25 crashes. 

• 2015 Crash Cost = 158,177 dollars × 2.47 = 390,697.20 dollars per crash. 

• Annual benefit from crashes saved = 41.25 crashes × 390,697.20 = 16,116,259 dollars. 

B/C Ratio: 

• B/C ratio = 16,116,259/4,174,947 = 3.86. 

Results: 

• Annual fatal and injury ROR crashes reduced: 41.25.

• 2015 crash cost for fatal and injury crashes: 390,697.20 dollars. 
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• Annualized construction cost: 4,174,947 dollars. 

• Annual benefit from crashes saved: 16,116,259 dollars. 

• B/C ratio: 3.86. 

The results indicate that while the targeted facilities experience an average 0.017 fatal and injury 

ROR crashes per mile, the installation is economically justified. The analysis indicates that 

approximately 41 fatal and injury ROR crashes would be reduced per year. 

Example Application 2 – High Crash Corridor Installation 

For a 2.5-mile section of rural, two-lane highway, an analyst identified the following information 

from a roadway inventory, crash database, and safety performance function: 

• AADT 5,500. 

• 2012 ROR Crashes: 8 Observed, 3.67 Predicted. 

o Predicted crashes from SPF for rural, two-lane highways. 

o In this example, SPF is assumed to be for ROR crashes. 

o Crashes/year = 5,500 × 2.5 × 365 × 10-6 × e(-0.312) = 3.67. 

o Overdispersion parameter = 0.236 / L = 0.236 / 2.5 = 0.0944. 

• 2013 ROR Crashes: 7 Observed, 3.67 Predicted. 

• 2014 ROR Crashes: 9 Observed, 3.67 Predicted. 

• Percent fatal and injury ROR crashes: 50 percent. 

The analyst is considering implementing CLRS and SRS in combination, for which the CMF 

Clearinghouse indicates the CMF to be 0.70. Other given information include the following: 

• 2001 crash cost for fatal and injury crashes: 158,177 dollars. 

• 2001 crash cost for property damage only crashes: 7,428 dollars. 

• Installation cost: 1,500 dollars per mile. 

• Rumble strip life expectancy: 7 years. 

Expected Number of Crashes: 

• Observed crash frequency = 8 + 7 + 9 = 24 crashes / 3 years = 8 crashes/year. 

• Annual correction factor = 1.0 for each year. 

• The weighted adjustment, w = 1 / (1 + 0.0944 × 11.01) = 0.49. 
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• The EB adjusted expected average crash frequency for year 1 = 0.49 × 3.67 + (1 – 0.49). 

× 24/3 = 5.88 crashes 

• The excess expected average crash frequency = 5.88 – 3.67 = 2.21 crashes/year 

This identifies that the corridor is a candidate for treatment for excess ROR crashes. The 

analyst determines that CLRS and SRS are candidate countermeasures and examines them 

further. 

Costs: 

• Installation cost = 1,500 dollars × 2 edge lines + center line = 4,500 dollars per mile. 

• Capital Recovery Factor = ((1 + 0.07)7 - 1)/(0.07 × (1 + 0.07)7) = 5.39. 

• Annualized construction cost = 4,500/5.389 = 835 dollars per mile. 

Benefits: 

• Annual ROR crashes saved = 5.88 crashes/year × (1 – 0.70) = 1.76 crashes/year. 

• Annual ROR crashes saved per mile = 1.76 / 2.5 = 0.70 crashes per mile. 

• Average crash cost = 158,177 × 0.50 + 7,428 × 0.50 = 82,803 dollars. 

• 2015 Crash Cost = 82,803 dollars × 2.47 = 204,522 dollars per crash. 

• Annual benefit from crashes saved = 0.70 crashes × 204,522 = 143,984 dollars. 

B/C Ratio: 

• B/C ratio = 143,984 / 835 = 172.4. 

Results: 

• Expected number of ROR crashes: 5.88 crashes/year. 

• Excess expected ROR crashes: 2.21 crashes/year = candidate for CLRS and SRS. 

• Annual crashes reduced per mile: 0.70 crashes/mile.

• 2015 crash cost for fatal and injury crashes: 204,522 dollars per crash. 

• Annualized construction cost: 835 dollars per mile.

• Annual benefits: 143,984 dollars. 

• B/C ratio: 172.4. 

The upper 95-percentile estimate of the CMF is 0.79, resulting in a reduction of 0.49 ROR 

crashes per mi per year. The annualized benefit is calculated to be 101,018 dollars per mile. The 

resulting B/C ratio is 121.0, indicating that even a conservative estimate of the reduction results 

in a highly cost-effect solution. 
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REFERENCES 

1) Liu, C. and T.J. Ye. Run-Off-Road Crashes: An On-Scene Perspective. Report No. DOT HS 

811 500. National Highway Traffic Safety Administration, Washington, D.C., July 2011. 

2) National Highway Traffic Safety Administration. Fatality Analysis Reporting System (FARS). 

Available at http://www.nhtsa.gov/FARS. Accessed May 12, 2016. 

3) McLaughlin, S., J. Hankey, S. Klauer, and T. Dingus. Contributing Factors to Run-Off-Road 

Crashes and Near-Crashes. Report No. DOT-HS-811-079, National Highway Traffic 

Safety Administration, Washington, D.C., 2009. 

4) Leuer, D. Fatal Run off the Road Crashes on Rural Two-Lane Two-Way Highways in 

Minnesota. Minnesota Department of Transportation, Office of Traffic, Safety, and 

Technology. August 2015. 

5) Leuer, D. Fatal Head-On Crashes on Rural Two-Lane Two-Way Highways in Minnesota. 

Minnesota Department of Transportation, Office of Traffic, Safety, and Technology, 

January 2015. 

6) Federal Highway Administration (FHWA). Rumble Strips and Rumble Stripes: Design and 

Construction. U.S. Department of Transportation, Washington, D.C. 

http://safety.fhwa.dot.gov/roadway_dept/pavement/rumble_strips/design-andconstruction.cfm. Accessed December 23rd, 2015. 

7) Torbic, D.J., J.M.Hutton, C.D.Bokenkroger, K.M.Bauer, D.W.Harwood, D.K.Gilmore, 

J.M.Dunn, J.J.Ronchetto, E.T.Donnell, H.J.Sommer III, P.Garvey, B. Persaud, and C.Lyon. 

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

Rumble Strips. Transportation Research Board, Washington, DC, 2009. 

8) Albin, R., V. Brinkley, J. Cheung, F. Julian, C. Satterfield, W. Stein, E. Donnell, H. McGee, 

A. Holzem, M. Albee, J. Wood, F. Hanscom. Low-Cost Treatments for Horizontal Curve 

Safety 2016. Report No. FHWA-SA-15-084. Federal Highway Administration Office of 

Safety, Washington, D.C., January 2016. 

9) American Association of State Highway and Transportation Officials (AASHTO). 

Highway Safety Manual. AASHTO, Washington, D.C., 2010. 

10) Council, F., Zaloshnja, E., Miller, T., and Persaud, B. Crash Cost Estimates by Maximum 

Police-Reported Injury Severity Within Selected Crash Geometries. FHWA-HRT05-051, 

FHWA, McLean, VA. 2005. 

11) Office of Management and Budget. Circular A-4: Regulatory Analysis. Washington, D.C., 

2003. 

12) Federal Highway Administration (FHWA). Rumble Strips and Rumble Stripes. U.S. 

Department of Transportation, Washington, D.C., 
DECISION SUPPORT GUIDE FOR THE INSTALLATION OF CENTER LINE AND SHOULDER RUMBLE STRIPS 

60 

http://safety.fhwa.dot.gov/roadway_dept/pavement/rumble_strips/. Accessed August 2nd, 

2016. 

13) Federal Highway Administration (FHWA). Rumble Strip Implementation Guide: 

Addressing Bicycle Issues on Two-Lane Roads. Report No. FHWA-SA-15-035, FHWA 

Office of Safety, Washington, D.C., 2016. 

14) Federal Highway Administration (FHWA). Technical Advisory: Shoulder and Edge Line 

Rumble Strips, T 5040.39, Revision 1, U.S. Department of Transportation. 2011. 

15) Federal Highway Administration (FHWA). Rumble Strip Implementation Guide: 

Addressing Noise Issues on Two-Lane Roads. Report No. FHWA-SA-15-033, FHWA 

Office of Safety, Washington, D.C., 2015. 

16) Federal Highway Administration (FHWA). Technical Advisory: Center Line Rumble 

Strips, T 5040.40, Revision 1, U.S. Department of Transportation. 2011. 

17) Federal Highway Administration (FHWA). Rumble Strip Implementation Guide: 

Addressing Pavement Issues on Two-Lane Roads. Report No. FHWA-SA-15-034, 

FHWA Office of Safety, Washington, D.C., 2015. 

18) Kailey, D. Rumble Strip Guidance [Memorandum]. Montana Department of 

Transportation, Helena, MT, 2015. 

19) Mulvihill, S. Rumble Strips and Stripes on Rural Trunk Highways [Memorandum 14-07-T-01]. 

Minnesota Department of Transportation, St. Paul, MN, 2014. 

20) Microsoft. Buffer median on Highway 14 from Bing Streetside. Available at 

https://binged.it/2bg7VHx. Accessed August 10, 2016. July 2015. 

21) Texas Traffic Safety Task Force. Solutions for Saving Lives on Texas Roads: Texas Traffic 

Safety Task Force Report. Texas Department of Transportation. Austin, TX, June 2016. 
For More Information:

Visit http://safety.fhwa.dot.gov/roadway_dept/pavement/rumble_strips/

FHWA, Office of Safety

Cathy Sattereld

cathy.sattereld@dot.gov

708-283-3552

FHWA-SA-16-115