Safety Evaluation of Profiled

Thermoplastic Pavement Markings

PUBLICATION NO. FHWA-HRT-17-075 MARCH 2018

Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101-2296
FOREWORD

The research documented in this report was conducted as part of the Federal Highway 

Administration (FHWA) Evaluation of Low-Cost Safety Improvements Pooled Fund Study 

(ELCSI–PFS). FHWA established this PFS in 2005 to conduct research on the effectiveness of 

the safety improvements identified by the National Cooperative Highway Research Program 

Report 500 Guides as part of implementation of the American Association of State Highway and 

Transportation Officials (AASHTO) Strategic Highway Safety Plan. The ELCSI-PFS research 

provides a crash modification factor and benefit–cost economic analysis for each of the targeted 

safety strategies identified as priorities by the pooled fund member States.

The profiled thermoplastic pavement markings evaluated in this study are intended to reduce the 

frequency of crashes by improving the visibility of pavement markings and providing a rumble 

effect. Geometric, traffic, and crash data were obtained from Florida and South Carolina. The 

combined results for the two States indicate consistent, though statistically insignificant, 

reductions in nighttime wet-weather crashes, the primary targets of the treatment. The results 

suggest that the treatment, even with conservative assumptions for cost, service life, and the value 

of a statistical life, can be cost effective. This document is intended for safety engineers, highway 

designers, planners, and practitioners at State and local agencies involved with AASHTO 

Strategic Highway Safety Plan implementation.

Monique R. Evans, P.E., CPM

Director, Office of Safety

Research and Development

Notice

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

(USDOT) 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 integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement.
TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No.

FHWA-HRT-17-075

2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle

Safety Evaluation of Profiled Thermoplastic Pavement Markings

5. Report Date

March 2018

6. Performing Organization Code

7. Author(s)

Craig Lyon, Bhagwant Persaud, and Kimberly Eccles

8. Performing Organization Report 

No.

9. Performing Organization Name and Address

VHB Persaud & Lyon, Inc.

8300 Boone Boulevard, Suite 700 87 Elmcrest Road

Vienna, VA 22182-2626 Toronto, ON M9C 3R7

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

DTFH61-13-D-00001

12. Sponsoring Agency Name and Address

U.S. Department of Transportation

Federal Highway Administration

1200 New Jersey Avenue, SE 

Washington, DC 20590-3660

13. Type of Report and Period 

Covered

Safety Evaluation

14. Sponsoring Agency Code

HRDS-20

15. Supplementary Notes

The Federal Highway Administration Office of Safety Research and Development Program and Task Manager was 

Ms. Roya Amjadi (HRDS-20).

16. Abstract

The Development of Crash Modification Factors (CMFs) program conducted safety evaluation of profiled 

thermoplastic pavement markings for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This 

study evaluated application of profiled thermoplastic pavement markings. This strategy involves upgrading existing 

markings from flat-line thermoplastic or other standard markings to the profiled product. These profiled markings 

are designed to provide an improved level of vision to drivers, particularly during wet-road surface conditions. 

Geometric, traffic, and crash data were obtained for two-lane and multilane road sections in Florida and South 

Carolina where the treatment was applied to the edge lines. To account for potential selection bias related to 

regression-to-the-mean, an empirical Bayes before–after analysis was conducted. The analysis controlled for changes 

in traffic volumes over time and time trends in crash counts unrelated to the treatment. Intersection-related, 

snow/slush/ice, and animal crashes were excluded from the analysis. Only nighttime wet-road crashes, a principal 

target crash type, exhibited a material change—an estimated CMF of 0.908. Although the estimated CMF was based 

on a small sample of crashes and was not statistically significant at the 95-percent confidence level, it was consistent 

between the two States, which suggests that its use might be justifiable. The benefit–cost ratio for flat-line 

thermoplastic markings was 3.65:1 based on the consistent reduction in nighttime wet-road crashes and estimated 

with conservative cost and service life assumptions. Applying the sensitivity analysis recommended by the U.S. 

Department of Transportation, this value could range from 2.01:1 to 5.04:1. These results suggest that the 

treatment—even with conservative assumptions on cost, service life, and the value of a statistical life—can be 

applied cost effectively despite the relatively small crash reduction effects.

17. Key Words

Profiled pavement marking, pavement marking 

visibility, pavement markings, low-cost, safety 

improvements, safety evaluations, wet-road surface 

conditions, empirical Bayes

18. Distribution Statement.

No restrictions. This document is available through the 

National Technical Information Service, 

Springfield, VA 22161.

http://www.ntis.gov

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

42

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized.
ii
iii

TABLE OF CONTENTS

EXECUTIVE SUMMARY...........................................................................................................1

CHAPTER 1. INTRODUCTION ................................................................................................3

BACKGROUND ON STRATEGY .........................................................................................3

BACKGROUND ON STUDY..................................................................................................4

LITERATURE REVIEW.........................................................................................................4

CHAPTER 2. OBJECTIVE .........................................................................................................7

CHAPTER 3. METHODOLOGY ...............................................................................................9

CHAPTER 4. DATA COLLECTION.......................................................................................13

FLORIDA ................................................................................................................................13

Installation Data ....................................................................................................................13

Reference Sites......................................................................................................................13

Roadway Data .......................................................................................................................13

Traffic Data ...........................................................................................................................14

Crash Data .............................................................................................................................14

Treatment Cost and Service Life Data ..................................................................................14

SOUTH CAROLINA..............................................................................................................14

Installation Data ....................................................................................................................14

Reference Sites......................................................................................................................14

Roadway Data .......................................................................................................................14

Traffic Data ...........................................................................................................................15

Crash Data .............................................................................................................................15

Treatment Cost and Service Life Data ..................................................................................15

DATA CHARACTERISTICS AND SUMMARY................................................................15

CHAPTER 5. DEVELOPMENT OF SPFS ..............................................................................19

FLORIDA ................................................................................................................................19

SOUTH CAROLINA..............................................................................................................20

CHAPTER 6. BEFORE–AFTER EVALUATION RESULTS...............................................23

AGGREGATE ANALYSIS....................................................................................................23

DISAGGREGATE ANALYSIS.............................................................................................24

CHAPTER 7. ECONOMIC ANALYSIS ..................................................................................25

CHAPTER 8. SUMMARY AND CONCLUSIONS.................................................................27

APPENDIX A. ADDITIONAL INSTALLATION DETAILS FROM FLORIDA ...............29

APPENDIX B. ADDITIONAL INSTALLATION DETAILS FROM SOUTH 

CAROLINA ...........................................................................................................................31

ACKNOWLEDGEMENTS........................................................................................................33

REFERENCES............................................................................................................................35
iv

LIST OF FIGURES

Figure 1. Photo. Raised profiled thermoplastic marking.(1)............................................................ 3

Figure 2. Photo. Inverted profiled thermoplastic marking.(1).......................................................... 3

Figure 3. Equation. Estimated change in safety. ............................................................................. 9

Figure 4. Equation. EB estimate of expected crashes. .................................................................. 10

Figure 5. Equation. EB weight. ..................................................................................................... 10

Figure 6. Equation. Index of effectiveness.(3)................................................................................ 10

Figure 7. Equation. Standard deviation of index of effectiveness.(3)............................................ 11

Figure 8. Equation. Form of SPFs for Florida............................................................................... 19

Figure 9. Equation. Form of SPFs for South Carolina. ................................................................. 20

Figure 10. Equation. Aggregate 2015 unit cost for total crashes calculation................................ 25

LIST OF TABLES

Table 1. Definitions of crash types by State.................................................................................. 16

Table 2. Strategy installation and crash data summary for treatment sites. .................................. 17

Table 3. Volume and roadway data summary for Florida sites. ................................................... 17

Table 4. Volume and roadway data summary for South Carolina sites........................................ 18

Table 5. Data summary for reference sites.................................................................................... 18

Table 6. Parameter estimates and SEs for SPFs for Florida two-lane roads................................. 19

Table 7. Parameter estimates and SEs for SPFs for Florida multilane roads................................ 20

Table 8. Parameter estimates and SEs for SPFs for South Carolina two-lane roads. ................... 21

Table 9. Parameter estimates and SEs for SPFs for South Carolina multilane roads. .................. 21

Table 10. Results for Florida......................................................................................................... 23

Table 11. Results for South Carolina. ........................................................................................... 23

Table 12. Combined results for Florida and South Carolina......................................................... 24
v

LIST OF ABBREVIATIONS

AADT annual average daily traffic 

B/C benefit–cost

CMF crash modification factor

DCMF Development of Crash Modification Factors (program)

EB empirical Bayes 

ELCSI-PFS Evaluation of Low-Cost Safety Improvements Pooled Fund Study

FDOT Florida Department of Transportation

FHWA Federal Highway Administration 

KABCO Scale used to represent injury severity in crash reporting (K is fatal injury, A is 

incapacitating injury, B is non-incapacitating injury, C is possible injury, and O is 

property damage only)

PFS pooled fund study

ROR run-off-road

SCDOT South Carolina Department of Transportation

SE standard error

SPF safety performance function 

USD U.S. dollar

USDOT U.S. Department of Transportation 

1

EXECUTIVE SUMMARY

The Federal Highway Administration (FHWA) established the Development of Crash 

Modification Factors (DCMF) program in 2012 to address highway safety research needs for 

evaluating new and innovative safety strategies (improvements) by developing reliable 

quantitative estimates of their effectiveness in reducing crashes. The ultimate goal of the DCMF 

program is to save lives by identifying new safety strategies that effectively reduce crashes and 

promote those strategies for nationwide implementation by providing measures of their safety 

effectiveness and benefit–cost (B/C) ratios through research. State transportation departments and 

other transportation agencies need to have objective measures for safety effectiveness and B/C 

ratios before investing in broad applications of new strategies for safety improvements.

Forty State transportation departments have provided technical feedback on safety improvements 

to the DCMF program and have implemented new safety improvements to facilitate evaluations. 

These States are members of the Evaluation of Low-Cost Safety Improvements Pooled Fund 

Study (ELCSI-PFS), which functions under the DCMF program.

This study selected profiled thermoplastic pavement markings as a strategy for evaluation. This 

strategy involved upgrading existing markings from flat-line thermoplastic or other standard 

markings to the profiled product. These markings are designed to provide an improved level of 

vision to drivers, particularly during wet-road surface conditions. The profiled nature also 

provides a rumble effect for errant vehicles. A literature review found no published research 

evaluating the effect on crashes after profiled thermoplastic pavement markings were applied. 

The project team obtained geometric, traffic, and crash data from Florida and South Carolina,

where the treatment was applied to edge lines of two-lane and multilane roads. To account for 

potential selection bias related to regression-to-the-mean, an empirical Bayes (EB) before–after 

analysis was conducted using reference groups of untreated road sections with characteristics 

similar to the treated sites. The analysis also controlled for changes in traffic volumes over time 

and time trends in crash counts unrelated to the treatment. The evaluation was done for the 

following crash types: total, injury, run-off-road (ROR), head-on, sideswipe-opposite-direction, 

sideswipe-same-direction, wet-road, nighttime wet-road crashes, and all nighttime crashes. None 

of these crash types included intersection-related, snow/slush/ice, and animal crashes.

Only nighttime wet-road crashes, a principal target crash type, exhibited a material change, with 

an estimated crash modification factor (CMF) of 0.908. Although the estimated CMF was based 

on a small sample of crashes and was not statistically significant at the 95-percent confidence 

level, it was consistent between the two States, which suggests that its use might be justifiable.

The B/C ratio for flat-line thermoplastic markings was 3.65:1, based on the consistent reduction 

in nighttime wet-road crashes and estimated with conservative cost and service life assumptions. 

Applying the sensitivity analysis recommended by the U.S. Department of Transportation

(USDOT), this value could range from 2.01:1 to 5.04:1. These results suggest that the 

treatment—even with conservative assumptions on cost, service life, and the value of a statistical 

life—can be applied cost effectively despite the relatively small crash reduction effects.

3

CHAPTER 1. INTRODUCTION

This chapter presents background information on the strategy of using profiled thermoplastic 

pavement markings, the goals of the study reported here, and a review of the existing literature on 

the use of profiled thermoplastic pavement markings.

BACKGROUND ON STRATEGY

Although policies have varied by jurisdiction, most roadways with any significant volume of 

traffic have included edge lines, center lines, and—in the case of multilane roadways—lane lines. 

These markings provide guidance to drivers on the intended vehicle path.

The treatment of interest is the use of profiled thermoplastic pavement markings. This treatment 

provides a rumble effect and enhances visibility compared with standard lane markings, 

particularly at night and during wet conditions. Because snowplowing can destroy this marking, 

its use is typically limited to locations characterized by warmer climates.

According to the Federal Highway Administration (FHWA), several agencies have used the 

treatment with good results, but none have conducted a safety effectiveness evaluation.

(1)

There are two types of profiled markings—raised and inverted profile patterns—as shown in 

figure 1 and figure 2.

Figure 1. Photo. Raised profiled thermoplastic marking.(1)

Figure 2. Photo. Inverted profiled thermoplastic marking.(1)
4

BACKGROUND ON STUDY

FHWA established the Development of Crash Modification Factors (DCMF) program in 2012 to 

address highway safety research needs for evaluating new and innovative safety strategies 

(improvements) by developing reliable quantitative estimates of their effectiveness in reducing 

crashes. The ultimate goal of the DCMF program is to save lives by identifying new safety 

strategies that effectively reduce crashes and to promote those strategies for nationwide 

implementation by providing measures of their safety effectiveness and B/C ratios through

research. State transportation departments and other transportation agencies need objective 

measures for safety effectiveness and benefit–cost (B/C) ratios before investing in broad 

applications of new strategies for safety improvements. Forty State transportation departments 

have provided technical feedback on safety improvements to the DCMF program and have 

implemented new safety improvements to facilitate evaluations. These States are members of the 

Evaluation of Low-Cost Safety Improvements Pooled Fund Study (ELCSI-PFS), which functions 

under the DCMF program.

The use of profiled thermoplastic pavement markings was selected as a strategy to be evaluated 

as part of this effort. 

LITERATURE REVIEW

A literature review found no published research evaluating the effect of profiled thermoplastic 

pavement markings on crashes. The following discussion of profiled thermoplastic pavement 

markings is a summary of the information provided in volume 4 of the National Cooperative 

Highway Research Program Report 500 Guides, which focused on center-line applications (in 

contrast to the States that provided data for this study and applied the profiled markings on edge 

lines).

(2)

Profiled markings provide an audible/tactile effect, although it is less noticeable to drivers of

larger vehicles, especially trucks. The effect is similar to that experienced when driving over

raised pavement markers with short spacing. While the audible/tactile effect can be 

advantageous, its principal benefit is improved visibility at night, in particular during wet 

conditions, compared with standard pavement markings. The treatment would be limited to areas 

where there is little or no snow because snowplow blades will easily scrape off the markings.

As of the date of this study, the strategy had not been sufficiently evaluated to be considered 

proven, but there had been no significant findings of negative effects.

Application of profiled thermoplastic markings has been typically recommended under the 

following conditions for two-lane rural roads:

• Snow removal is not required.

• No-passing zones are relatively long.

• Volume levels and crash experience do not justify more costly treatments.
5

• Resurfacing or other pavement maintenance activities that would cause removal of the 

treatment are not scheduled for at least 3 years.

• The areas have higher than normal rainfall. 

• These markings can be used as an incremental improvement when more cost-intensive 

projects are being designed and funded.

There have been no significant obstacles or difficulties in using this treatment, although its use 

may not be suitable for open-graded or seal-coated surfaces. No adverse effects have been 

reported for motorcycles.

7

CHAPTER 2. OBJECTIVE

This research examined the safety impacts of using profiled thermoplastic pavement markings in 

Florida and South Carolina in comparison with more conventional markings, including a flat-line 

thermoplastic product. The objective was to estimate the safety effectiveness of this strategy as 

measured by crash frequency. Intersection-related, snow/slush/ice, and animal crashes were 

excluded. The following target crash types were considered:

• Total crashes (all types and severities combined).

• Injury crashes (K, A, B, and C injuries on the KABCO scale, where K is fatal injury, A is 

incapacitating injury, B is non-incapacitating injury, C is possible injury, and O is 

property damage only).

• Run-off-road (ROR) crashes (all severities combined).

• Head-on crashes (all severities combined).

• Sideswipe-opposite-direction crashes (all severities combined).

• Sideswipe-same-direction crashes (all severities combined).

• Wet-road crashes (all types and severities combined).

• Nighttime crashes (all types and severities combined).

• Nighttime wet-road crashes (all types and severities combined).

A further objective was to investigate ways in which effects might vary, such as the following:

• By roadway type.

• By level of traffic volumes.

• By posted speed limit.

• By shoulder width.

• By lane width.

• By the site-specific expected crash frequency prior to treatment.

• By the overall effect, measured by the economic costs of crashes by crash type and severity.

The evaluation of overall effectiveness included consideration of the installation costs and crash 

savings in terms of the B/C ratio. 

Meeting these objectives placed some special requirements on the data collection and analysis 

tasks, including the following:

• Selecting a large enough sample size to detect, with statistical significance, what may be 

small changes in safety for some crash types.
8

• Identifying appropriate untreated reference sites.

• Properly accounting for changes in safety due to changes in traffic volume and other 

nontreatment factors.

• Pooling data from multiple jurisdictions to improve reliability of the results and to 

facilitate broader applicability of the products of the research.
9

CHAPTER 3. METHODOLOGY

The empirical Bayes (EB) methodology for observational before–after studies was used for the 

evaluation conducted in this study. This methodology is considered rigorous in that it accounts 

for regression-to-the-mean using a reference group of similar but untreated sites. In the process, 

safety performance functions (SPFs) were also used to do the following:

• Overcome the difficulties of using crash rates in normalizing for volume differences 

between the before and after periods.

• Account for time trends.

• Reduce the level of uncertainty in the estimates of the safety effects.

• Account for differences in crash experience and reporting practice in amalgamating data 

and results from diverse jurisdictions.

The methodology derived and documented in detail by Hauer is only summarized here. It also

provides a foundation for developing guidelines for estimating the likely safety consequences of a 

contemplated strategy.(3) The SPFs for roadways without profiled thermoplastic pavement

markings can be used with observed crash histories to estimate the number of crashes without 

treatment, and the crash modification factors (CMFs) developed can be applied to this number to 

estimate the number of crashes with treatment.

In the EB approach, the estimated change in safety for a given crash type at a site is given by the 

equation in figure 3.

Figure 3. Equation. Estimated change in safety.

Where:

= Expected number of crashes that would have occurred in the after period without the strategy.

= Number of reported crashes in the after period. 

In estimating , the effects of regression-to-the-mean and changes in traffic volume were 

explicitly accounted for using SPFs, which relate crashes of different types to traffic flow and 

other relevant factors for each jurisdiction based on untreated sites (i.e., reference sites). Annual 

SPF multipliers were calibrated to account for temporal effects on safety (e.g., variation in 

weather, demography, and crash reporting).

In the EB procedure, the SPF is first used to estimate the number of crashes that would be 

predicted to occur in each year of the before period at reference sites having traffic volumes and 

other characteristics similar to the one being analyzed. The sum of these annual SPF estimates 

(P) is then combined with the count of crashes (x) in the before period at a strategy site to obtain 

 Safety = λ - π

λ

π

λ
10

an estimate of the predicted number of crashes (m) before strategy. This estimate of m is

calculated using the equation in figure 4.

Figure 4. Equation. EB estimate of expected crashes.

Where w is estimated from the mean and variance of the SPF estimate using the equation in 

figure 5.

Figure 5. Equation. EB weight.

Where k is an overdispersion parameter estimated from the SPF calibration. 

In specifying the SPF, a negative binomial distributed error structure is assumed, with k being the 

overdispersion parameter of this distribution and that is estimated along with the other parameters 

of the SPF.

A factor is then applied to m to account for the length of the after period and differences in traffic 

volumes between the before and after periods. This factor is the sum of the annual SPF 

predictions for the after period divided by P, the sum of these predictions for the before-period. 

The result, after applying this factor, is an estimate of . The procedure also produces an estimate 

of the variance of .

The estimate of is then summed over all sites in a strategy group of interest (to obtain sum) and 

compared with the count of crashes observed during the after period in that group ( sum). The 

variance of is also summed over all sites in the strategy group. 

The index of effectiveness ( ) is estimated using the equation in figure 6.

Figure 6. Equation. Index of effectiveness.(3)

The standard deviation of is given by the equation in figure 7.

m = w(P)+(1-w)(x)

w =

1

1+ kP

λ

λ

λ λ

π

λ

θ

















2

( )

1

sum

sum

sum

sum

Var











θ
11

Figure 7. Equation. Standard deviation of index of effectiveness.(3)

The percent change in crashes is calculated as 100(1  ); thus, a value of  0.70 with a 

standard error (SE) of 0.12 indicates a 30-percent reduction in crashes with an SE of 12 percent.

2

2

2 2

2

( )

1

( ) ( )

( )







































sum

sum

sum

sum

sum

sum

Var

Var Var

StDev

















θ θ

13

CHAPTER 4. DATA COLLECTION

Florida and South Carolina provided data, including the locations and dates of the installation of 

profiled thermoplastic pavement markings. Reference sites were also identified in each State that

were similar to the treated sites in terms of traffic volumes and roadway geometry but had other 

than profiled thermoplastic lane markings. These States also provided roadway geometry, traffic 

volumes, crash data, and information on other construction activities for both installation and 

reference sites. This section summarizes the data assembled for the analysis.

FLORIDA

This section describes the installation data, reference sites, roadway data, traffic data, crash data, 

and treatment cost and service life data for Florida sites used in this evaluation.

Installation Data

The Florida Department of Transportation (FDOT) provided a list of installations of profiled 

thermoplastic markings. FDOT applied the treatment mostly on rural two-lane undivided roads 

with some use on rural multilane divided roadways. The profiled markings were used for the 

edge lines. The treatment site data provided include the following installations:

• 27 mi in 2007–2008.

• 138 mi in 2009.

• 292 mi in 2010.

• 58 mi in 2011.

• 119 mi in 2012.

Data from the year of installation were excluded from analysis. No other construction activities 

were reported at these locations.

Reference Sites

Reference sites were chosen by selecting roadways in the same counties as the treated locations 

with the same functional class and similar levels of traffic volume and geometrics.

Roadway Data

FDOT provided roadway inventory data that included the following variables:

• Functional class.

• Urban versus rural environment.

• Number of lanes.

• Speed limit.

• Surface width.

• Shoulder width.

• Median type.

• Median width.
14

Traffic Data

FDOT provided traffic data from 2005 to 2013 in the form of annual average daily traffic (AADT). 

Crash Data

FDOT provided crash data from 2005 to 2013, including many variables related to the location, 

time, and characteristics of each crash. 

Treatment Cost and Service Life Data

A range of treatment cost and service life data were provided by FDOT for various contracts. 

Examination of these data suggested that they were reasonably consistent with the more specific 

information available for South Carolina, so it was decided to apply the South Carolina 

Department of Transportation (SCDOT) costs for the economic analysis based on the combined 

results of the two States.

The information provided by FDOT suggested that a service life of 3 years could be assumed.

SOUTH CAROLINA

This section describes the installation data, reference sites, roadway data, traffic data, crash data, 

and treatment cost and service life data for South Carolina sites used in this evaluation.

Installation Data

SCDOT provided a list of installations of profiled thermoplastic markings. Most installations 

were on rural two-lane undivided roads but with some installations on rural multilane divided 

roadways. The markings were only applied on the edge lines, and application took place in 2011 

and 2012. Additional installations in the northern districts of the State had subsequently been 

removed through snowplowing operations, and these were not included in this study. Data for the 

installation year were excluded from the analysis. The total length of installations used for this 

study was 341 mi. The installation information included the route number, mileposts, and 

construction period. 

No other construction activities were reported at these locations.

Reference Sites

Reference sites were chosen by selecting rural two-lane and multilane roadways with 

characteristics similar to the treated sites and from the same districts as the treated sites.

Roadway Data

SCDOT provided roadway data from 2005 to 2014 that included the following variables:

• Number of lanes.

• Surface width.

• Shoulder width.
15

• Shoulder type.

• Median type.

• Median width.

Traffic Data

SCDOT provided traffic data from 2005 to 2014 in the form of AADT. 

Crash Data

SCDOT provided crash data for 2005 to 2014, including many variables related to the location, 

time, and characteristics of each crash.

Treatment Cost and Service Life Data

SCDOT provided estimated cost information of $0.50/linear ft for profiled thermoplastic 

pavement markings. The application cost for edge-line applications was $5,280/mi for two-lane 

roads and $10,560/mi for four-lane divided roads. The estimated service life is 5 to 7 years.

For flat-line thermoplastic pavement markings typical of the untreated reference sites, SCDOT 

estimated an installation cost of $0.40/linear ft, with a service life estimated at 5 years.

DATA CHARACTERISTICS AND SUMMARY

Table 1 defines the crash types used for both States. The project team attempted to make the 

crash type definitions consistent. In both States, intersection-related, snow/slush/ice, and animal 

crashes were excluded because these crash types were not considered correctable by the treatment 

under study. Note that sideswipe crashes in Florida were not analyzed because a coding change 

occurred during the study period; no sideswipe crashes were reported in later years at the 

treatment sites, and the crash coding for sideswipe crashes was not considered reliable.
16

Table 1. Definitions of crash types by State.

Crash Type Florida South Carolina

Total Location is coded as not at 

intersection, and First Harmful 

Event not animal, and Road 

Surface Condition not icy. 

Junction Type not an intersection 

type; First Harmful Event not 

deer or other animal; and Road 

Surface Condition not snow, 

slush, or ice.

Injury Crash resulted in at least one 

fatality or injury.

Number of fatalities or injuries 

equal to 1 or more.

ROR First Harmful Event indicates 

struck a roadside or off-roadway 

object.

First Harmful Event Location is 

roadside or outside trafficway,

and crash is not sideswipe-samedirection, sideswipe-oppositedirection, or head-on.

Sideswipe-samedirectionFirst Harmful Event is sideswipe. Manner of Collision is 

sideswipe-same-direction.

Sideswipe-oppositedirectionFirst Harmful Event is sideswipe. Manner of Collision is 

sideswipe-opposite-direction

Head-on First Harmful Event is head-on. Manner of Collision is head-on.

Wet-road Road Surface Condition is wet. Road Surface Condition is wet.

Nighttime Light condition is dark with or 

without lights.

Light Condition is dark with or 

without lights.

Nighttime wet-road Crash is defined as both wet-road 

and nighttime.

Crash is defined as both wet-road 

and nighttime.

Table 2 provides summary information for the data collected for the treatment sites. The 

information in table 2 should not be used to make simple before–after or between State 

comparisons of crashes per mile-year because such comparisons would not account for factors, 

other than the strategy, that might cause differences in safety between the before and after periods

or between States. Such comparisons are properly done with the EB analysis, as presented later.
17

Table 2. Strategy installation and crash data summary for treatment sites.

Variable Florida South Carolina

Number of miles 508.05 341.27

Mile-years before 2,521.40 2,176.19

Mile-years after 1,348.70 788.89

Crashes/mi/year before 1.32 0.97

Crashes/mi/year after 0.80 0.99

Injury crashes/mi/year before 0.73 0.38

Injury crashes/mi/year after 0.44 0.36

ROR crashes/mi/year before 0.32 0.30

ROR crashes/mi/year after 0.13 0.37

Head-on crashes/mi/year before 0.03 0.02

Head-on crashes/mi/year after 0.02 0.02

Sideswipe-same-direction crashes/mi/year before N/A 0.04

Sideswipe-same-direction crashes/mi/year after N/A 0.05

Sideswipe-opposite-direction crashes/mi/year before N/A 0.03

Sideswipe-opposite-direction crashes/mi/year after N/A 0.04

Wet-road crashes/mi/year before 0.24 0.18

Wet-road crashes/mi/year after 0.15 0.20

Nighttime crashes/mi/year before 0.44 0.31

Nighttime crashes/mi/year after 0.26 0.33

Nighttime wet-road crashes/mi/year before N/A 0.07

Nighttime wet-road crashes/mi/year after N/A 0.07

N/A = Not applicable. 

Table 3 and table 4 provide summary information for the volume and roadway data for the 

treatment sites, and table 5 provides summary information for the reference site data. 

Comparisons of crash rates between States and between treatment and reference sites should 

consider that the rates were only per mi and traffic volumes were not considered. 

Table 3. Volume and roadway data summary for Florida sites.

Variable

Treatment Reference

Average Minimum Maximum Average Minimum Maximum

AADT before 9,830 120 133,762 13,422 472 110,056

AADT after 9,657 120 132,500 N/A N/A N/A

Average outside 

shoulder width (ft)

5.00 2.00 18.00 4.97 1.00 23.00

Average inside 

shoulder width (ft)

3.00 2.00 10.00 2.52 1.00 11.00

Number of lanes 3.00 2.00 10.00 2.00 2.00 10.00

Posted speed limit 

(mi/h)

54.00 25.00 70.00 51.28 25.00 70.00

Surface width (ft) 20.00 20.00 120.00 35,015 18.00 120.00

Median width (ft) 13.00 0.00 236.00 18.36 0.00 106.00

N/A = Not applicable.
18

Table 4. Volume and roadway data summary for South Carolina sites.

Variable

Treatment Reference

Average Minimum Maximum Average Minimum Maximum

AADT before 5,881 120 23,371 7,094 450 37,644

AADT after 5,549 120 23,050 N/A N/A N/A

Average outside 

shoulder width (ft) 6.21 0.00 12.00 5.57 0.00 12.00

Average inside 

shoulder width (ft) 0.33 0.00 10.00 0.07 0.00 4.00

Number of lanes 2.41 2.00 4.00 2.78 2.00 6.00

Posted speed limit 

(mi/h) N/A N/A N/A N/A N/A N/A

Surface width (ft) 29.79 20.00 66.00 34.09 18.00 78.00

Median width (ft) 9.17 0.00 99.00 12.08 0.00 106.00

N/A = Not applicable.

Table 5. Data summary for reference sites.

Variable Florida South Carolina

Number of miles 982.89 142.70

Mile-years 8,845.98 1,427.0

Crashes/mi/year 1.25 2.09

Injury crashes/mi/year 0.70 0.69

ROR crashes/mi/year 0.21 0.45

Head-on crashes/mi/year 0.02 0.06

Sideswipe-same-direction crashes/mi/year N/A 0.17

Sideswipe-opposite-direction crashes/mi/year N/A 0.03

Wet-road crashes/mi/year 0.21 0.41

Nighttime crashes/mi/year 0.37 0.61

Nighttime wet-road crashes/mi/year 0.07 0.13

N/A = Not applicable.
19

CHAPTER 5. DEVELOPMENT OF SPFs

This chapter presents the SPFs developed for each State. The SPFs were used in the EB 

methodology to estimate the safety effectiveness of this strategy.(3) Generalized linear modeling 

was used to estimate model coefficients assuming a negative binomial error distribution, which is 

consistent with the state of research in developing these models. In specifying a negative 

binomial error structure, the overdispersion parameter, k, used in the EB calculations, was 

estimated iteratively from the model and the data. For a given dataset, smaller values of k indicate 

relatively better models. Estimates of k are provided, along with other model parameters.

SPFs were calibrated separately for Florida and South Carolina using the corresponding reference 

sites from each State. The SPFs developed are presented by State in the following sections.

FLORIDA

Figure 8 presents the form of the SPFs for Florida, which are presented in table 6 for two-lane 

roads and in table 7 for multilane roads. 

Figure 8. Equation. Form of SPFs for Florida.

Where:

AADT = Annual average daily traffic volume.

urbrur = Urban or rural indicator (1 if rural; 0 if urban).

lanes = Number of lanes indicator (1 if two-lane road; 0 if multilane road).

outshldwid = Total width of outside shoulder in ft.

a, b, c, d, e = Parameters estimated in the SPF calibration process.

Table 6. Parameter estimates and SEs for SPFs for Florida two-lane roads.

Crash Type a (SE) b (SE) c (SE) d (SE) e (SE) k (SE)

Total −6.1605

(0.8484)

0.7494

(0.0801)

−0.2376

(0.1281)

−0.7743

(0.3066) —

0.9997

(0.0961)

Injury −6.6533

(0.8948)

0.7324

(0.0850)

−0.2019

(0.1351)

−0.7081

(0.3151) —

0.8710

(0.1087)

ROR −4.7588

(0.7815)

0.3733

(0.0875) — —

−0.0724

(0.0374)

1.0195

(0.1496)

Wet-road −7.8781

(0.8857)

0.6753

(0.0998) — —

−0.0983

(0.0478)

0.7622

(0.1895)

Nighttime −8.9148

(0.7447)

0.8750

(0.0844) — —

−0.0724

(0.0374)

1.0195

(0.1496)

Nighttime wet-road −9.5244

(1.4369)

0.6709

(0.1647) — — —

1.5210

(0.6474)

For the head-on crash type, the total crash SPFs were used with a multiplier of 2.5 percent.

k is the estimated overdispersion parameter of the SPF.

— Indicates the variable associated with this parameter was not included in the SPF. 

Crashes

mile − year

= exp

aAADTb expc∗urbrur +d∗lanes +e∗outs hldwid
20

Table 7. Parameter estimates and SEs for SPFs for Florida multilane roads.

Crash Type a (SE) b (SE) c (SE) d (SE) e (SE) k (SE)

Total −10.4061

(0.4791)

1.1516

(0.0493) — — —

0.9346

(0.0564)

Injury −10.0352

(0.5059)

1.0494

(0.0518) — — —

0.8486

(0.0613)

ROR −6.6828

(0.6114)

0.5621

(0.0626) — — —

1.0824

(0.1165)

Wet-road −13.1037

(0.7157)

1.2323

(0.0724) — — —

1.0926

(0.1116)

Nighttime −10.1507

(0.5544)

0.9945

(0.0566) — — —

0.7552

(0.0677)

Nighttime wet-road −12.8712

(0.9752)

1.0912

(0.0982) — — —

1.1884

(0.2054)

For the head-on crash type, the total crash SPF was used with a multiplier of 1.5 percent.

k is the estimated overdispersion parameter of the SPF.

— Indicates the variable associated with this parameter was not included in the SPF.

SOUTH CAROLINA

The form of the SPFs for South Carolina, which are presented in table 8 and table 9, is shown in 

figure 9.

Figure 9. Equation. Form of SPFs for South Carolina.

Where:

Length = segment length in mi.

WIDTH = total lane width in ft.

Crashes

year

= exp

aAADTb Lengthcexpd∗WIDTH
21

Table 8. Parameter estimates and SEs for SPFs for South Carolina two-lane roads.

Crash Type a (SE) b (SE) c (SE) d (SE) k (SE)

Total −4.6715

(1.0491)

0.8865

(0.1326)

0.6618

(0.0754)

−0.0902

(0.0310)

0.5065

(0.1121)

Injury −4.1584

(1.1961)

0.7081

(0.1483)

0.7489

(0.0870)

−0.0968

(0.0418)

0.4419

(0.1385)

ROR −2.4670

(1.1849)

0.5305

(0.1474)

0.8336

(0.0904)

−0.1153

(0.0463)

0.3736

(0.1187)

Head-on + sideswipe-oppositedirection−8.5087

(1.7023)

0.7328

(0.2087)

0.9831

(0.1650) —

0.3830

(0.3248)

Sideswipe-same-direction −10.6206

(2.3048)

0.9467

(0.2800)

0.5159

(0.1520) —

0.5231

(0.4623)

Wet-road −5.7593

(1.1402)

0.8714

(0.1348)

0.7403

(0.0892)

−0.1146

(0.0453)

0.1601

(0.0917)

Nighttime −4.3691

(1.0210)

0.6535

(0.1248)

0.7327

(0.0764)

−0.0660

(0.0335)

0.2625

(0.0916)

For the nighttime wet-road crash type, the total crash SPF was used with a multiplier of 8 percent.

k is the estimated overdispersion parameter of the SPF.

— Indicates the variable associated with this parameter was not included in the SPF.

Table 9. Parameter estimates and SEs for SPFs for South Carolina multilane roads.

Crash Type a (SE) b (SE) c (SE) d (SE) k (SE)

Total −18.2646

(1.4823)

2.0712

(0.1578)

0.7742

(0.0717) —

0.2524

(0.0884)

Injury −15.7429

(1.5549)

1.6966

(0.1635)

0.7458

(0.0758) —

0.5953

(0.2394)

ROR −6.0470

(3.0778)

0.5845

(0.3276)

1.0229

(0.1434) —

0.5953

(0.2394)

Head-on + sideswipe-samedirection−20.5081

(3.3853)

1.9528

(0.3442)

0.8685

(0.1508) —

0.1024

(0.1716)

Sideswipe-same-direction −17.9590

(2.0064)

1.8196

(0.2068)

0.8101

(0.0943) —

0.1228

(0.1131)

Wet-road −18.8293

(2.1940)

1.9640

(0.2296)

0.7955

(0.1072) —

0.3254

(0.1529)

Nighttime −17.4415

(1.6741)

1.8433

(0.1750)

0.8167

(0.0824) —

0.1581

(0.0786)

For the nighttime wet-road crash type, the total crash SPF was used with a multiplier of 8 percent.

k is the estimated overdispersion parameter of the SPF.

— Indicates the variable associated with this parameter was not included in the SPF.

23

CHAPTER 6. BEFORE–AFTER EVALUATION RESULTS

AGGREGATE ANALYSIS

Table 10 details the Florida results, and table 11 details the South Carolina results. These results 

include the estimates of predicted crashes in the after period without treatment, the observed

crashes in the after period, and the estimated CMF and its SE for all crash types considered. The 

results were consistent between the two States in that no CMF results were statistically 

significantly different from 1.0. Both States also indicated a modest reduction in total crashes and 

a reduction in nighttime wet-road crashes of approximately 10 percent, although these were not 

statistically significant at the 95-percent confidence level.

Table 10. Results for Florida.

Crash Type

EB Estimate of 

Crashes 

Predicted in 

After Period 

Without Strategy

Count of 

Crashes 

Observed in 

After Period

Estimate of 

CMF

SE of Estimate 

of CMF

Total 1,136.28 1,085 0.954 0.035

Injury 582.48 590 1.012 0.049

ROR 182.59 172 0.941 0.080

Head-on 19.47 24 1.229 0.259

Wet-road 204.13 201 0.983 0.078

Nighttime 348.31 352 1.010 0.062

Nighttime wet-road 63.52 58 0.910 0.129

Table 11. Results for South Carolina.

Crash Type

EB Estimate of 

Crashes 

Predicted in 

After Period 

Without Strategy

Count of 

Crashes 

Observed in 

After Period

Estimate of 

CMF

SE Error of 

Estimate of 

CMF

Total 789.81 779 0.986 0.041

Injury 312.59 281 0.898 0.060

ROR 254.45 292 1.146 0.078

Head-on + sideswipeopposite-direction49.09 44 0.894 0.143

Sideswipe-samedirection35.57 36 1.009 0.177

Wet-road 152.73 157 1.027 0.089

Nighttime 281.57 261 0.926 0.064

Nighttime wet-road 60.76 55 0.903 0.131
24

Table 12 provides the results for the combined Florida and South Carolina data for the crash 

types analyzed in both States. Even with the combined data, none of the estimated CMFs were 

statistically significant at the 95-percent confidence level.

Table 12. Combined results for Florida and South Carolina.

Crash Type

EB Estimate of 

Crashes 

Predicted in 

After Period 

Without Strategy

Count of 

Crashes 

Observed in 

After Period

Estimate of 

CMF

SE of Estimate 

of CMF

Total 1,926.09 1,864 0.968 0.027

Injury 895.07 871 0.973 0.038

ROR 437.04 464 1.061 0.056

Wet-road 356.86 358 1.003 0.059

Nighttime 629.87 613 0.973 0.045

Nighttime wet-road 124.28 113 0.908 0.092

DISAGGREGATE ANALYSIS

An attempt was made to further analyze the combined dataset for nighttime wet-road crashes to 

identify site characteristics for which the safety benefits might be greatest. Only nighttime wetroad crashes were considered because this was a key target crash type and the only one that 

showed some consistency and sizable effect for both States; however, the CMF estimates were 

still not statistically significant at the 95-percent confidence level.

The following variables were investigated:

• Number of lanes.

• Surface width.

• Average shoulder width.

• Median width.

• AADT.

• Expected nighttime wet-road crash frequency per mi prior to treatment.

The project team saw no differences or clear trends in the estimated CMF for any of the 

geometric variables or AADT. Therefore, for this dataset, the expected effect of this strategy on 

nighttime wet-road crashes was the same, regardless of differences in these aspects of the 

roadway environment.

There were some indications that the CMF for nighttime wet-road crashes might be smaller (a 

larger benefit) for sites with higher expected nighttime wet-road crash frequency per mi prior to 

treatment. However, the sample was too small for a robust conclusion in this regard.
25

CHAPTER 7. ECONOMIC ANALYSIS

The project team conducted an economic analysis to determine the estimated B/C ratio for this 

strategy. Nighttime wet-road crashes, which were reduced, were considered for this analysis. The 

observed benefit—a CMF of 0.908—was not unexpected because this was the principal target 

crash type. Although the estimated CMF was based on a small sample of crashes and was not 

statistically significant at the 95-percent confidence level, it was consistent between the 

two States, which suggests that it was justified to use it for this purpose.

On the cost side, specific costs and information provided by SCDOT were used because these were 

reasonably consistent with the range of costs provided by FDOT for various contracts. It was 

conservatively assumed that the base condition that characterized the reference group of untreated 

sites consisted of flat-line thermoplastic pavement markings with a cost of $0.40/linear ft. The cost 

provided for profiled thermoplastic markings was $0.50/linear ft, so the relative cost of 

$0.10/linear ft was used as the unit treatment cost for the analysis. With these assumptions, the 

estimated treatment cost for the two States combined was $524,691.

Although service lives of between 3 and 5 years were provided by the two transportation 

departments, the analysis assumed, conservatively, a useful service life for safety benefits of 

2.5 years, the average after-period length at the treatment sites. 

Based on information from the Office of Management and Budget’s Circular A-4, the project 

team used a real discount rate of 7 percent to calculate the annual cost of the treatment based on 

the 2.5-year service life.

(4) With this information, the installation costs converted to annual costs 

of $125,926. 

For the benefit calculations, the most recent FHWA mean comprehensive crash costs were used 

as a base.

(5) Council et al. developed these costs based on 2001 crash costs and found that the unit 

costs (in 2001 U.S. dollars (USD)) for property damage only and fatal plus injury crashes for all 

speed limits combined were $7,428 and $158,177, respectively.(5) These were updated to 2015

USD by applying the ratio of the U.S. Department of Transportation’s (USDOT’s) 2015 value of 

a statistical life of $9.4 million to the 2001 value of $3.8 million.(6) By applying this ratio of 2.47

to the unit costs for property damage only and fatal plus injury crashes and then weighting by the 

frequencies of these two crash types in the after period (from table 12), the aggregate 2015 unit 

cost for total crashes was obtained as shown in figure 10.

Figure 10. Equation. Aggregate 2015 unit cost for total crashes calculation.

Fatal crashes were not considered independently because of the very low numbers of such 

crashes in the data, which would skew the results. 

The project team calculated the crash reduction by subtracting the actual crashes in the after 

period from the expected crashes in the after period had the treatment not been implemented

(based on table 12). The number of nighttime wet-road crashes saved per year was 4.48, which 

2.47*(7,428*(993/1,864)+158,177*(871/1,864)) = $192,337
26

the project team obtained by dividing the crash reduction of 11.28 by the average number of 

after-period years per site (2.52). 

The annual benefit (i.e., crash savings) of $862,033 was the product of the crash reduction per 

year (4.48) and the aggregate costs of a crash, with all severities combined ($192,337). The B/C 

ratio of 3.65:1 was calculated as the ratio of the annual benefit to the annual cost. USDOT 

recommends conducting a sensitivity analysis by assuming values of a statistical life 0.55 and 

1.38 times the recommended 2015 value.(6) These factors can be applied directly to the estimated 

B/C ratio to obtain a range of 2.01:1 to 5.04:1. These results suggest that the treatment, even with 

conservative assumptions on cost, service life, and the value of a statistical life, can be cost 

effective despite the relatively small crash reduction effects.
27

CHAPTER 8. SUMMARY AND CONCLUSIONS

The objective of this study was to undertake a rigorous before–after evaluation of the safety 

effectiveness of profiled thermoplastic pavement markings applied to edge lines as measured by 

crash frequency. The study used data from two-lane and multilane roads in two States—Florida 

and South Carolina—to examine the effects for specific crash types, including total, fatal plus 

injury, ROR, head-on, sideswipe-opposite-direction, sideswipe-same-direction, wet-road, 

nighttime, and nighttime wet-road crashes. Only nighttime wet-road crashes, the principal target 

crash type, exhibited a material change, yielding a CMF of 0.908, which was not unexpected 

because this was the primary target crash type. Although the estimated CMF was based on a 

small sample of crashes and was not statistically significant at the 95-percent confidence level, it 

was consistent between the two States, which suggests its use may be justifiable.

Based on the consistent reduction in nighttime wet-road crashes and estimated with conservative 

cost and service life assumptions, the B/C ratio relative to flat-line thermoplastic markings was 

3.65:1. Applying the sensitivity analysis recommended by USDOT, this value could range from

2.01:1 to 5.04:1. These results suggest that the treatment—even with conservative assumptions 

on cost, service life, and the value of a statistical life—can be cost effective.

With additional data, future research may provide statistically significant results for those crash 

types for which a CMF could not be recommended or for which a CMF was insignificant where 

recommended, as well as more informative analyses to develop disaggregate CMFs that reflect 

different application circumstances.

29

APPENDIX A. ADDITIONAL INSTALLATION DETAILS FROM FLORIDA

This appendix presents additional details provided by FDOT regarding its installations of profiled 

thermoplastic pavement markings. 

1. Can you provide average installation costs per line-mile and the estimated service life of the 

products used?

Average cost for a 6-inch 100 mil above-surface thickness extruded with bump 

material could average somewhere between $3,275 to $3,900 [per] gross lane mile. 

Service life as required by specification is 3 years.

2. Are raised or inverted profile patterns applied?

Raised patterns are used; inverted profile is no longer allowed by specification.

3. On which of edge lines, center lines, and lane lines are profiled thermoplastic markings 

applied?

Yellow and white edge lines are specified; center line has to have a documented history 

of crossover accidents to be warranted.

4. Can you provide any installation guidelines for the markings (e.g., width, spacing, pavement 

types on which the markings are not suitable)?

Our requirements for Specification 701 in Florida is [a] 6-inch line, audible bump is 

spaced at approximately [a] 30-inch spacing, [and] materials are allowed on both 

asphalt and concrete surfaces by Specification 701.

Specification 701 is available at the following link: http://www.dot.state.fl.us/

programmanagement/Implemented/SpecBooks/January2016/Files/701-116.pdf.

5. Are there any criteria for deciding which roads receive the profiled thermoplastic markings 

(e.g., a certain level of AADT or critical crash rate)? 

As of January 21, 2015, policy is to use profiled thermoplastic on concrete pavements 

for edge lines and center lines on all rural, two-lane and multi-lane, flush shoulder, 

non-limited access facilities, where posted speed is 50 mi/h or greater.

http://www.dot.state.fl.us/rddesign/Bulletin/RDB15-02.pdf

6. Were any other safety countermeasures installed at the treatment sites evaluated by this study 

in conjunction with the profiled thermoplastic markings?

None reported.

7. Please describe any notable challenges related to the installation of the markings and how you 

overcame them.
30

None reported.

8. Please describe any notable challenges related to the maintenance of the markings and how 

you overcame them.

None reported.

9. What lessons learned or recommendations would you share with another agency interested in 

the widespread application of profiled thermoplastic markings?

None reported.
31

APPENDIX B. ADDITIONAL INSTALLATION DETAILS FROM SOUTH CAROLINA

This appendix presents additional details provided by SCDOT regarding its installations of 

profiled thermoplastic pavement markings.

1. Can you provide average installation costs per line-mile and the estimated service life of the 

products used?

An average cost would be $0.50/linear ft. Service life of 5 years.

2. Are raised or inverted profile patterns applied?

Primarily, raised profiles are used, and the thermoplastic is preferred to the disc but 

both are allowed.

3. On which of edge lines, center lines, and lane lines are profiled thermoplastic markings 

applied?

Typically, the edge line only is treated.

4. Can you provide any installation guidelines for the markings (e.g., width, spacing, pavement 

types on which the markings are not suitable)?

Criteria for rumble strips including profiled thermoplastic markings [are] available at:

http://info.scdot.org/Construction_D/Engineering%20Directive%20Memorandums/ED

M53.pdf.

Specifications [are] available at: http://www.scdot.org/doing/technicalpdfs/supspecs/

profile_marking_system.pdf.

5. Are there any criteria for deciding which roads receive the profiled thermoplastic markings 

(e.g., a certain level of AADT or critical crash rate)? 

Rumble strips shall be placed on shoulders or edge lines of all partial and noncontrolled access roadways, subject to the following criteria: 

a. Roadway is classified as rural.

b. ADT [average daily traffic] is 500 vehicles per day or greater.

c. Posted speed limit is 45 mi/h or greater.

d. Existing roadway width is 20 ft or greater.

Thermoplastic profiled markings are an acceptable alternative only if rumble stripes 

are not feasible due to structural insufficiencies of a paved shoulder where milled in 

rumble strips may damage the surface/shoulders.

6. Were any other safety countermeasures installed at the treatment sites evaluated by this study 

in conjunction with the profiled thermoplastic markings?
32

A select few projects may have been through resurfacing efforts but is minimal.

7. Please describe any notable challenges related to the installation of the markings and how you 

overcame them.

Not aware of any challenges.

8. Please describe any notable challenges related to the maintenance of the markings and how 

you overcame them.

Their use is limited due to the short lifecycle and comparable cost to milled in rumble 

strips. We are not necessarily a snow State, but any snow removal or shoulder leveling 

would practically remove the markings.

9. What lessons learned or recommendations would you share with another agency interested in 

the widespread application of profiled thermoplastic markings?

Obviously, use of the profile should be in a State with limited snow activity. One 

should also consider that when shoulders are leveled that the profiled marking will 

likely be removed. Where possible, milled-in rumble strips should be the preferred 

method based on cost and longevity.
33

ACKNOWLEDGEMENTS

This report was prepared for the Federal Highway Administration Office of Safety Research and 

Development under contract DTFH61-13-D-00001. The FHWA Program and Task Manager for 

this project was Ms. Roya Amjadi.

The project team gratefully acknowledges the participation and assistance of the following 

organizations in this study:

• Florida Department of Transportation.

• South Carolina Department of Transportation.

35

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Treatments for Horizontal Curve Safety, Report No. FHWA-SA-07-002. Available at 

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December 22, 2015.

2. Neuman, T.R., Pfefer, R., Slack, K.L., Hardy, K.K., Council, F., McGee, H., Prothe, L., and 

Eccles, K. (2003). Volume 4: A Guide for Addressing Head-On Collisions, Transportation 

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3. Hauer, E. (1997). Observational Before–After Studies in Road Safety—Estimating the Effect 

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4. Office of Management and Budget. (2003). Circular A-4: Regulatory Analysis, Office of 

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circulars_a004_a-4/. Last accessed December 15, 2015.

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Maximum Police-Reported Injury Severity Within Selected Crash Geometries, Report No. 

FHWA HRT-05-051, Federal Highway Administration, Washington, DC.

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HRDS-20/03-18(200)E