Synthesis of Pavement Marking Research

www.safety.fhwa.dot.gov
02

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 integrity of its information. FHWA periodically reviews quality issues and adjusts its 

programs and processes to ensure continuous quality improvement. 
i

 June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

Form DOT F 1700.7 (8-72)

1. Report No. 

FHWA-SA-15-063

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

4. Title and Subtitle 

Synthesis of Pavement Marking Research

5. Report Date

June 2015

6. Performing Organizations Code

7. Authors

 Paul J. Carlson

8. Performing Organization Report No.

9. Performing Organization Name and Address

Leidos, Inc. Texas A&M Transportation Institute

11951 Freedom Drive The Texas A&M University System

Reston, VA 20190 College Station, Texas 77843-3135

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

 Contract DTFH61-10-D-000024

12. Sponsoring Agency Name and Address

Office of Safety

Federal Highway Administration

1200 New Jersey Avenue, SE

Washington, DC 20590

13. Type of Report and Period Covered

Final Report

14. Sponsoring Agency Code

HSA

15. Supplementary Notes

Projects were performed with the cooperation and participation of the Federal Highway Administration, U.S. 

Department of Transportation. 

Project Title: Highway Safety Visibility Program Technial Assistance

16. Abstract

This report provides a synthesis of recent research focused on longitudinal pavement markings. It offers a review 

of when and where longitudinal pavement markings are used. It also covers two of the most important parameters 

in terms of increasing the effectiveness of pavement markings: width and retroreflectivity. These items are within 

the control of owners and operators. By better understanding how width and retroreflectivity impact operational 

performance, visibility, and safety, highway agencies can increase the effectiveness of their pavement marking 

policies. This synthesis is intended to provide a reference about what is known on the subject and what questions still 

remain. The research recommendations are based on the synthesized material. Ongoing or pending research that is 

known is noted where appropriate.

17. Key Words

retroreflectivity, traffic control devices, pavement markings, operational 

performance, visibility, safety, durability

18. Distribution Statement 

No restrictions. 

19. Security Classif. (of this report) 

Unclassified

20. Security Classif. (of this page) 

Unclassified

21. No of Pages

 34

22. Price 

 

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

June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

SI* (MODERN METRIC) CONVERSION FACTORS

APPROXIMATE CONVERSIONS TO SI UNITS

SYMBOL WHEN YOU KNOW MULTIPLY BY TO FIND SYMBOL

LENGTH

in

ft

yd 

mi

inches

feet

yards

miles

25.4

0.0305

0.914

1.61

millimeters

meters

meters

kilometers

mm

m

m

km

AREA

in2

ft2

yd2

ac

mi2

square inches

square feet

square yard

acres

square miles

645.2

0.093

0.836

0.405

2.59

square millimeters

square meters

square meters

hectacres

square kilometers

mm2

m2

m2

ha

km2

VOLUME (NOTE: volumes greater than 1000 L shall be shown in m3)

fl oz

gal

ft3

yd3

fluid ounces

gallons

cubic feet

cubic yards

29.57

3.785

0.028

0.765

millileters

liters

cubic meters

cubic meters

mL

L

m3

m3

MASS

oz

lb

T

ounces

pounds

short tons (2000 lb)

28.35

0.454

0.907

grams

kilograms

megagrams (or "metric ton")

g

kg

Mg (or "t")

TEMPERATURE (exact degrees)

oF Fahrenheit 5 (F-32)/9 or (F-32)/1.8 Celsius oC

ILLUMINATION

fc

fl

foot-candles

foot-Lamberts

10.76

3.426

lux

candela/m2

lx

cd/m2

FORCE and PRESSURE or STRESS

lbf

lbf/in2

poundforce

poundforce per square inch

4.45

6.89

newtons

kilopascals

N

kPa

APPROXIMATE CONVERSIONS FROM SI UNITS

LENGTH

mm

m

m

k

millimeters

meters

meters

kilometers

0.039

3.28

1.09

0.0621

inches

feet

yards

miles

in

ft

yd 

mi

AREA

mm2

m2

m2

ha

km2

square millimeters

square meters

square meters

hectacres

square kilometers

0.0016

10.764

1.19

2.47

0.386

square inches

square feet

square yard

acres

square miles

in2

ft2

yd2

ac

mi2

VOLUME

mL

L

m3

m3

millileters

liters

cubic meters

cubic meters

0.034

0.264

35.314

1.307

fluid ounces

gallons

cubic feet

cubic yards

fl oz

gal

ft3

yd3

MASS

g

kg

Mg (or "t")

grams

kilograms

megagrams (or "metric ton")

0.035

2.202

1.103

ounces

pounds

short tons (2000 lb)

oz

lb

T

TEMPERATURE (exact degrees)

oF Fahrenheit 1.8C+32 Celsius oC

ILLUMINATION

lx

cd/m2

lux

candela/m2

0.929

0.2919

foot-candles

foot-Lamberts

fc

fl

FORCE and PRESSURE or STRESS

N

kPa

newtons

kilopascals

0.225

0.145

poundforce

poundforce per square inch

lbf

lbf/in2

*SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380.

 (Revised March 2003)
iii

 June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

Table of Contents

CHAPTER 1: Introduction .............................................................................................................................................................................................1

Background..................................................................................................................................................................................................................1

Purpose of this Report..........................................................................................................................................................................................1

Organization of this Report................................................................................................................................................................................2

Report Summary ......................................................................................................................................................................................................2

CHAPTER 2. MUTCD Warrants....................................................................................................................................................................................4

CHAPTER 3. Pavement Marking Width ................................................................................................................................................................5

 Operational Performance.....................................................................................................................................................................................5

Visibility...........................................................................................................................................................................................................................5

Safety .............................................................................................................................................................................................................................6

CHAPTER 4: Dry Pavement Marking Retroreflectivity...............................................................................................................................8

Operational Performance ..................................................................................................................................................................................8

Visbility ............................................................................................................................................................................................................................8

Safety ...........................................................................................................................................................................................................................10

Test Methods and Specifications.................................................................................................................................................................12

CHAPTER 5: Wet Pavement Marking Retroreflectivity ............................................................................................................................13

Operational Performance ................................................................................................................................................................................13

Visibility.........................................................................................................................................................................................................................13

Durability .....................................................................................................................................................................................................................14

Test Methods and Specifications.................................................................................................................................................................15

CHAPTER 6: Combined Impacts of Markers..................................................................................................................................................16

CHAPTER 7. Pavement Marking Selection Tools.........................................................................................................................................19

CHAPTER 8. Future of Pavement Markings......................................................................................................................................................20

CHAPTER 9. Other Topics of Interest .................................................................................................................................................................21

References .......................................................................................................................................................................................................................... 22
iv

June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

List of Figures

Figure 1. Graph. Pavement marking detection distance as a function of retroreflectivity.(27)..........................................9

Figure 2. Bar chart. Comparison of visibility by delineation type.(46)...............................................................................................17

Figure 3. Screenshot. Results screen.(49)...................................................................................................................................................................................................................................................19
v

 June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

List of Abbreviations and Symbols

AADT Annual average daily traffic

AASHTO American Association of State Highway and Transportation Officials

FHWA Federal Highway Administration

mcd/m2/lx millicandelas per square meter per lux

MoDOT Missouri Department of Transportation

MUTCD Manual on Uniform Traffic Control Devices

NCHRP National Cooperative Highway Research Program

NCDOT North Carolina Department of Transportation

NPA Notice of Proposed Amendments

QR Quick Response

RFID Radio frequency identification 

RRPM Raised retroreflective pavement marker

vpd Vehicles per day
vi

June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 
1

 Chapter 1: Introduction | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 1: Introduction

BACKGROUND

Pavement markings are a relatively new concept in the overall history of paved roads. Prior to the mid-1900s, the majority of 

our highways were “naked”—highways without white and yellow pavement markings that exist on all major highways in the 

United States today. The research on adding markings to naked highways goes back over half a century when most highways did 

not have markings. While the findings from these studies are based on naïve statistical analysis methods, the studies all clearly 

indicate that pavement markings provide crash reductions.(1–4) A 2004 synthesis on pavement marking research includes a brief 

description of the value of installing pavement markings on naked highways.(1)

Pavement markings delineate the travel lanes and other features of the roadway, providing benefits that are inherently linked 

to safety. Pavement markings provide lane position assistance in the near field and roadway alignment guidance in the far field. 

They have been designed to be visible to drivers in both day and night conditions. Pavement marking research has covered 

topics such as durability, visibility, vehicle operational impacts using speed and lane position, and safety impacts using crash 

types such as run-off-the-road and head-on crashes. Less research has been devoted toward how to cost-effectively optimize 

the performance of pavement markings—i.e., their durability, best practices on size and brightness, and interactions with other 

treatments such as roadway lighting or raised pavement markers. Some other questions that may need more research are:

• When are markings needed? 

• What types of markings should be used? 

• How should the markings be maintained? 

• Do narrow highways need both center line and edge line markings? If not, is one safer than the other? 

• What width should pavement markings be? 

• How bright do they need to be? 

• How can pavement markings be optimized when used in areas with roadway lighting and/or raised

pavement markers? 

• What is the value of different types of glass bead coatings? 

• How round do the glass beads (the optics of most markings) need to be? 

More research is needed to definitively answer these questions and determine specific methods of enhancing the performance 

of pavement markings. 

PURPOSE OF THIS REPORT

This report provides a synthesis of recent research focused on longitudinal pavement markings. It offers a review of the United 

States standards for when and where longitudinal pavement markings are used. It also covers two of the most important 

parameters in terms of increasing the effectiveness of pavement markings: width and retroreflectivity. These items are within 

the control of owners and operators. By better understanding how width and retroreflectivity impact performance, highway 

agencies would be able to increase the effectiveness of their pavement marking policies and improve safety. 

This synthesis is intended to provide a reference about what is known on the subject and what questions still remain. The 

research recommendations are based on the synthesized material. Ongoing or pending research that is known is noted 

where appropriate. 
2

June 2015 | Chapter 1: Introduction 

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

ORGANIZATION OF THIS REPORT

The structure of this report is based on the parameters that impact pavement marking placement and performance. The report 

is structured as follows:

• Chapter 2 summarizes when and where longitudinal pavement marking are typically installed.

• Chapter 3 addresses research findings related to longitudinal pavement marking width. 

• Chapter 4 addresses research findings related to pavement marking retroreflectivity, based on the factors within the 

control of highway owners/operators. 

• Chapter 5 addresses wet nighttime pavement marking retroreflectivity. Although wet pavement marking 

retroreflectivity is a subset of retroreflectivity described in Chapter 4, this chapter is separated out due to heightened 

interest in this area.

• Chapter 6 addresses the impacts of raised retroreflective pavement markers (RRPMs).

• Chapter 7 describes research that provides guidance on selecting the most appropriate pavement marking materials.

• Chapter 8 includes thoughts concerning the future of pavement markings.

• Chapter 9 briefly describes related topics not specifically addressed in this report. 

Chapters 3 through 5 are divided into three key performance metrics: operational impacts, visibility, and safety. Where 

appropriate, standards and specifications are summarized. Each section of this report includes a brief summary and 

recommendations for future research. Remarks are also provided where ongoing work is underway or pending. 

Specifically excluded from this synthesis are object markers and pavement marking design issues that are the purview of the 

Manual on Uniform Traffic Control Devices (MUTCD). Additionally, this report does not include pavement marking symbols, 

crosswalk markings, and marking types other than traditional longitudinal markings. This is a synthesis of research rather than a 

synthesis of practice.

REPORT SUMMARY

The MUTCD describes when and where longitudinal pavement markings shall and should be installed, using criteria based 

on traffic volume, roadway width, and functional classification. When the MUTCD criteria were drafted, specific research was 

not available to help set the criteria. Research results (such as those from the Missouri Department of Transportation [MoDOT] 

described in Chapter 2) have become available and suggest that there may be enhanced safety benefits to implementing criteria 

more aggressive than those currently described in the MUTCD warrants. However, additional research may be needed to assess 

what criteria would be appropriate. 

The default pavement marking width is generally 4 inches in the United States, although 6-inch wide pavement markings are 

also used. The width of pavement markings up to 6 inches has negligible impacts on operating speed and lateral placement 

on two-lane highways. Additional research regarding the operational performance of pavement markings wider than 6 inches 

or on highways other than two-lane, two-way facilities may be of interest. Regarding visibility of wider lines, there are some 

inconsistencies in the research, but the most recent studies indicate that wider pavement markings can increase pavement 

marking visibility. Research also has shown that wider pavement markings may provide a way to reduce driver workload along 

horizontal curves. 
3

 Chapter 1: Introduction | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

More research is needed to understand the trade-offs between using wider and brighter pavement markings. Many agencies 

strive for higher retroreflectivity levels without considering wider markings. Increasing pavement marking width may offer 

more benefits than installing and/or maintaining markings with relatively high retroreflectivity levels. Wider pavement markings 

have been shown to have a positive safety relationship on rural two-lane, two-way highways; however, on multilane divided 

highways, wider pavement markings have not been found to have a significant positive safety impact. 

The research on the effects of dry pavement marking retroreflectivity has demonstrated little to no impact on operational 

measures of performance such as vehicle speed or lateral placement. While research of this type is generally focused within 

horizontal curves, the findings are likely to be similar along tangent sections. If additional research is performed in this area, it 

should include new considerations, such as studying the benefits of retroreflectivity when dry conditions are not ideal (e.g., 

when on-coming vehicles are approaching and nighttime visibility is limited). 

Research shows that pavement marking detection distance provides an objective way to measure pavement marking visibility, 

although it may not be directly tied to a specific driving task. Subjective studies and visibility modeling have been used to 

determine visibility-derived recommendations for minimum maintained retroreflectivity levels. If additional research in performed 

in this area, it should include objective human factors testing with an aim to derive replacement retroreflectivity levels. 

As more data become available, research on the relationship between retroreflectivity and safety is starting to show consistent 

evidence that specifying and maintaining adequate pavement marking retroreflectivity can increase safety. Additional research 

is needed to strengthen the understanding of how specific retroreflectivity levels impact nighttime safety. 

Currently, a national model for a performance-based specification for pavement marking retroreflectivity does not exist. 

While a test method and specification for handheld pavement marking retroreflectivity measurements exist, similar test 

methods and specifications for mobile equipment do not. There is also no national certification program for mobile 

retroreflectivity measurements, which are similar to other mobile measurements such as pavement friction. 

Wet-retroreflectivity is one of the newest topics of interest for pavement marking performance. The research on its effects 

show, like dry pavement marking retroreflectivity, that wet pavement marking retroreflectivity performance does not impact 

operational measures of performance such as vehicle speed or lateral placement. Additional research in this area could include 

new considerations, such as determining the benefits of retroreflectivity during wet conditions and when driving can be 

particularly challenging (e.g., driving on undivided highways with opposing vehicle headlamp glare). 

Research has shown that dry retroreflectivity is almost always higher than wet retroreflectivity, but wet performance cannot be 

predicted based on dry retroreflectivity measures. The wet retroreflectivity performance is very dependent on the pavement 

marking optics. More work is needed to validate appropriate research recommendations for minimum wet retroreflectivity. 

Additional research is also needed to understand how wet retroreflective pavement marking visibility affects nighttime crashes. 

Markings that provide long-lasting wet retroreflectivity performance are not yet widely available. Initial research results with a 

new, more controlled ASTM test method for measuring the performance of pavement markings under a continuous condition of 

wetting indicate placing wet-night markings in a groove may be necessary (at least in climates with regular snow plow activities) 

to help maintain an adequate performance level. The ASTM test method for continuous wetting has recently been approved; 

however, there are still some concerns about the repeatability of the test method. 

Other items in this report include a discussion of the combined impacts of raised pavement markers, pavement marking 

selection tools, ideas about the future of pavement markings, and a list and brief description of other important aspects of 

pavement markings.
4

June 2015 | Chapter 2: MUTCD Warrants

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 2. MUTCD Warrants

Longitudinal pavement markings (center lines, lane lines and edge lines) are a traffic control device and are included in the 

MUTCD. The MUTCD defines characteristics of pavement markings such as width, pattern, and color. The MUTCD also includes 

the standards that define when and where pavement markings are used on roadways in the United States. 

The 1993 Department of Transportation Appropriations Act directed the FHWA to include warrants for longitudinal pavement 

markings in the MUTCD. The Markings Technical Committee of the National Committee on Uniform Traffic Control Devices 

provided FHWA with warrant criteria recommendations based upon available research and engineering judgment for center line 

and edge line markings. FHWA concluded a series of rulemaking efforts on January 3, 2000, when the final rule modifying the 

MUTCD was adopted by establishing warrants for center line and edge line longitudinal pavement markings. The warrants are 

based on traffic volume, functional classification, and roadway width. 

Since the pavement marking warrants were added to the MUTCD, several studies have been conducted regarding the safety 

effect of applying more aggressive criteria than the MUTCD warrants. The most recent study was released in 2013, in which 

MoDOT investigated the safety effects of striping edge lines on low-volume rural highways (i.e., roadways with annual average 

daily traffic [AADT] of 400 to 1,000 vehicles per day [vpd]). Prior to this study, MoDOT’s policy was to stripe routes with an AADT 

of 1,000 vpd or greater with both an edge line stripe and a center line, while routes with traffic volume less than 1,000 vpd only 

had a center line stripe. By adding edge lines to routes with 400 vpd or greater, MoDOT increased the number of miles of fully 

striped roadways by nearly 7,500 miles.(5)

MoDOT started the additional edge line striping in 2009 and completed it in 2012. One district completed its eligible routes in 

2009—the 570 center line miles of highways in that district were used in this study. A total of 576 crashes occurred on these 

highways from 2006 to 2008. Of these 576 crashes, 105 involved either a fatal or disabling injury crash (35 severe crashes per year). 

Of the severe crashes, 79 involved the run-off-the-road right crash type. Overall, there were a total of 340 run-off-the-road right 

crash types in the combined locations.

The after data included years 2010 and 2011. During this two-year span, a total of 327 total crashes occurred, 46 of which involved 

either a fatal or disabling injury crash (23 severe crashes per year). Of the severe crashes, 31 involved the run-off-the-road right 

crash type. Overall, there were a total of 173 run-off-the-road right crash types in the combined locations.

Using the empirical Bayes method for analysis, the study showed a 15.2 percent decrease in total crashes for all crash types 

(significant at the 95 percent confidence level). In addition, severe crashes decreased by 19.3 percent (though this data was not 

able to gain statistical significance due to the small sample size). 

SUMMARY: The MUTCD warranting criteria are based on traffic volume, roadway width, and functional classification. 

When the MUTCD warranting criteria were drafted, no specific research was available to help set the criteria. For agencies 

interested in increasing safety on low volumes highways, there is now research suggesting that enhanced safety benefits 

can be obtained by implementing more aggressive criteria than those currently in the MUTCD. Additional research is needed 

to assess specific thresholds for defining the added safety. 
5

 Chapter 3: Pavement Marking Width | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 3. Pavement Marking Width

In the United States, most longitudinal markings are nominally 4 inches wide. The MUTCD defines the width of a normal 

pavement marking as 4 to 6 inches, and a wide pavement marking as at least twice the width of a normal marking (at least 

8 inches). In practice, however, many agencies consider 6-inch wide longitudinal pavement markings to be wide markings. 

As demonstrated in this chapter, much of the research on pavement marking width also considers 6-inch pavement markings 

to be wide. 

OPERATIONAL PERFORMANCE

A 2013 study published by FHWA includes a literature review of the impacts of pavement marking width on observed driver 

speed and lateral placement; however, the findings of the review were inconclusive.(6) The same FHWA report includes a 

before-and-after study of vehicle speed and vehicle lateral placement approaching and throughout horizontal curves on twolane highways. The study produced findings similar to the previous research. While some particular instances of either lateral 

placement and/or change in speed were found to be statistically significant, the findings were not consistent and the magnitude 

of the change was not deemed practical. For the conditions studied, it appears that wider edge lines had no practical impact in 

terms of vehicle lateral placement and speed.

SUMMARY: Based on the latest research, the width of pavement markings up to 6 inches has negligible impacts on 

operating speed and lateral placement on two-lane highways. Additional research regarding the operational performance 

of pavement markings wider than 6 inches or on highways other than two-lane, two-way facilities may be beneficial. 

VISIBILITY

A motorist operating a vehicle uses pavement markings to guide him or her along the roadway. It is generally believed that, to 

be effective, pavement markings must be easily seen—increasing the width of the markings is one way to increase their visibility. 

Some agencies have reported that the visual appearance of wider pavement markings is enough to justify their use because 

the roadway looks better and even safer compared to 4-inch markings.(7) In general, research provides some evidence to 

suggest that drivers can see wider markings at longer distances. These improvements may improve lane keeping and positively 

impact safety. 

Researchers have performed multiple studies to evaluate pavement marking visibility as it relates to width. The results of 

pavement marking width studies from the 1980s and early 1990s are inconclusive in terms of identifying visibility gains. 

Some research showed increased visibility for wider lines,(8,9,10) while other research showed no consistently statistical or 

practical differences.(11,12) More recent studies have provided more consistent results. 

A 1995 study found that increasing pavement markings from 4 inches to 8 inches provides a statistically significant increase 

in average detection distances for young drivers on a left curve.(8) A 2001 study found that 6-inch markings have a statistically 

significant improvement over 4-inch markings for detection distances among both older and younger drivers under dry 

conditions at night.(11) A 1996 simulator study found that 8-inch markings provide a marginal improvement in average detection 

distance over 4-inch markings for both older and younger drivers at low levels of marking brightness.(14)

A 2006 study found that increasing markings from 4 inches to 6 inches resulted in an increase in detection distance, but 

found no increase in detection distance when increasing width from 6 inches to 8 inches.(13) A 2010 study comparing various 

4 inch and 6 inch markings under wet and dry conditions found that some markings can produce marginal improvements 

in detection distances under wet conditions.(15) The findings show that the structural design of the marking, combined with 

the type of retroreflective optics, is an important aspect to understand in terms of the relationship between width and visual 
6

June 2015 | Chapter 3: Pavement Marking Width

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

nighttime performance under both dry and wet conditions. A 2006 empirical study showed that theoretical calculations of 

marking detection distance as a function of marking width are invalid, and more work is needed to develop the mathematical 

relationships between marking width and detection distances.(20)

A 2010 eye-tracking study suggests that increasing edge line width from 4 to 6 to 8 inches along horizontal curves provides a 

reduced driver workload in the driving environment by providing more time for drivers to focus their foveal (central) vision on 

critical driving tasks.(16) The same study also determined that brighter pavement markings did not impact driver eye-looking 

patterns. Combined, these findings suggest that increasing the width of pavement markings may be more valuable than 

increasing their retroreflective performance—at least above a particular retroreflective threshold that may be adequate.

SUMMARY: Although the research has some inconsistencies, the most recent studies indicate that wider pavement 

markings can increase detection distance. Research has shown that wider pavement markings may provide a way to reduce 

driver workload along horizontal curves. More research is needed to understand the trade-offs between using wider and 

brighter pavement markings. Increasing pavement marking width may provide more benefits than those gained from 

installing and/or maintaining markings with relatively high retroreflectivity levels. 

SAFETY

Being perhaps the most important performance indicator of the effect of pavement marking width, safety evaluations have 

been reported for nearly two decades. In general, as more data are available and more advanced study techniques are 

implemented, the effect of pavement marking width is better understood; however, the effect of increasing pavement marking 

width by 2 inches has been elusive. Some agencies have reported that the visual appearance of wider pavement markings is 

enough to justify their use because the roadway looks safer.(7)

In 1987, a study from Virginia evaluated wider edge lines using a before-and-after approach with run-off-the-road and oppositedirection crashes. The data were from three years prior to installing 8-inch wide edge lines and two years after installation 

at three test sections.(17,18) The analysis resulted in a 13.6 percent reduction in both run-off-the-road and opposite-direction 

crashes, which was not statistically significant when compared to the comparison sites. Another 1987 before-and-after crash 

study conducted in New Mexico suggested that wider lines have no safety benefit in terms of reducing crashes.(15) Both of these 

studies were hampered by insufficient data.

In 2012, researchers presented the most comprehensive analysis yet of wider pavement markings and their impacts on the 

frequency and severity of non-intersection/interchange non-winter crashes (in terms of frequency and severity).(29) The analysis 

excluded intersection and interchange crashes as well as those in the winter months of November through March. Researchers 

studied the data from two-lane highways from three different States using current statistical analysis techniques to handle the 

unique characteristics of the data, including differences of how, when, and the extent to which States made the transition to 

wider lines. Also adding to the challenge was the implementation process and timing of transitioning to wider edge lines in each 

State. 

This detailed approach provided a number of results and while there are minor differences among the results, they all indicate 

consistent and positive safety effects of wider edge lines on two-lane highways. The crash frequency analysis suggests that 

wider edge lines are effective in reducing the frequency of crashes on rural two-lane highways, especially with regard to relevant 

target crashes such as single-vehicle crashes and run-off-the-road crashes.(6)

The same study also tried to identify the safety benefits of pavement markings wider than 4 inches on multilane divided 

highways. Using similar approaches but with less data, the research failed to produce the same conclusive findings. At the 
7

 Chapter 3: Pavement Marking Width | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

same time, the wider edge line markings were not shown to be a detriment either. One of the possible explanations is the 

standards to which these different types of roads are built. Since many two-lane highways have lower design standards than 

multilane facilities, it is not unreasonable to expect that subtle changes like adding 2 inches of pavement marking width will 

have a measurable impact on the lower standard highways. This is an interesting finding because agencies often prioritize the 

placement of wider pavement markings on multilane divided highways before their two-lane, two-way highways. 

In a follow-up study, researchers developed and compared benefit-cost ratios for wide edge line markings and other low-cost 

safety countermeasures such as rumble strips and post-mounted delineators.(21) Using earlier research findings,(29) specifically the 

conclusion that wider edge lines have been shown to reduce total target crashes 15 to 30 percent and fatal plus injury target 

crashes 15 to 38 percent, the researchers estimated that the benefit-cost ratio for wide edge lines is $33 to $55 for 

each $1 spent. Coincidentally, this benefit-cost ratio is similar to the benefit-cost ratio for rumble strips alone, although there 

are obvious differences between the two countermeasures. While rumble strips address crashes where the driver is distracted, 

drowsy, or inattentive and can be effective even when obscured by snow or rain, wider edge lines seem to be most effective 

where the driver is looking at the roadway/striping, or where the driver’s peripheral vision is detecting the marking.(22)

SUMMARY: Wider edge line pavement markings have been shown to have a positive safety relationship on rural twolane two-way highways. They also provide a high benefit-cost ratio on these roadways. However, on multilane divided 

highways, wider pavement markings have not been found to have a significant positive safety impact. The North Carolina 

Department of Transportation (NCDOT) is currently conducting a follow-up study to validate the safety benefits described 

for rural two-lane, two-way highways. The research described here provides possible justification for wider edge lines on 

some roads. Future research could be of interest to determine the safety benefits of wider markings on horizontal curves 
8

June 2015 | Chapter 4: Dry Pavement Marking Retroreflectivity

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 4: Dry Pavement Marking Retroreflectivity

In addition to the width of pavement markings, agencies can also control the retroreflectivity level of markings. Retroreflectivity 

is a nighttime characteristic of the marking, but since crashes are overrepresented during nighttime conditions, the effect of 

retroreflectivity is a focus of many research projects. Generally speaking, agencies can specify the retroreflectivity of newly 

installed markings, which is common. Agencies can also specify the performance level of pavement markings as they wear. 

While this is not as common as specifying retroreflectivity levels for newly installed markings, the concept is being used 

more frequently.

The vast majority of specified pavement marking retroreflectivity levels are for dry markings, not wet markings. This section 

summarizes work related specifically to dry pavement marking retroreflectivity. Wet pavement marking retroreflectivity is the 

focus of Chapter 5. 

OPERATIONAL PERFORMANCE 

A 2007 FHWA study reported on the effectiveness of pavement marking delineation on curves to induce consistency in vehicle 

speed and lateral position based on a nighttime driving experiment.(23) This was a well-controlled field study where conditions 

of a specific two-lane, two-way rural highway were changed from night to night and participants drove the section in an 

instrumented vehicle. The research showed that the use of brighter pavement markings (during dry conditions) does not 

improve speed consistency between an approach tangent and the midpoint of a horizontal curve. The same study showed that 

the use of brighter pavement markings does not affect the driver lane position differential between an approach tangent and 

the midpoint of a horizontal curve. 

SUMMARY: Pavement marking retroreflectivity has not been shown to impact operational measures of performance such 

as vehicle speed or lateral placement. While research of this type is generally focused within horizontal curves, there is no 

reason to think that the findings would be different along tangent sections. If additional research is performed in this area, 

it should include new considerations (e.g., the benefits of retroreflectivity when dry conditions are not ideal, such as when 

oncoming vehicles are approaching and nighttime visibility is limited). 

VISIBILITY 

Pavement marking visibility studies typically use detection distance as the measure of effectiveness. Detection distance has 

been measured in different ways. In a static setup, the driver counts the number of skip lines visible. In a dynamic setup, where 

the research participant is driving the vehicle, the driver is tasked with detecting either the beginning or end of a long line, an 

isolated skip line,(24) or a discontinuity such as a taper.(25) The results are reported in maximum nighttime detection distances. 

These studies have repeatedly shown that pavement marking detection distances increase as retroreflectivity increases, but the 

relationship is not linear.(26,27) In other words, if the retroreflectivity level is doubled, the detection distance will increase, but it will 

not be doubled. Research findings from a human factors experiment are shown in Figure 1. The research included pavement 

markings with retroreflectivity levels of 100, 300, and 800 mcd/m2/lx. For the 100 mcd/m2/lx marking, the average detection 

distance was about 300 feet. Increasing the retroreflectivity to 300 mcd/m2/lx produced about another 100 feet of detection 

distance, and then increasing the retroreflectivity to 800 produced about another 100 feet of detection distance. 
9

 Chapter 4: Dry Pavement Marking Retroreflectivity | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

Figure 1. Graph. Pavement marking detection distance as a function of retroreflectivity.(27)

While several studies have been conducted to determine minimum maintained retroreflectivity levels, they have been 

conducted in different ways. Subjective studies have been performed that use rating of various pavement markings in situ. In 

these studies, nighttime drives are conducted while the research participant rates the markings. Using measured retroreflectivity 

levels for the same markings, researchers assess the participants’ ratings of the same markings. Most of these types of subjective 

studies show that markings with retroreflectivity levels of 100 ± 30 mcd/m2/lx are preferred minimum levels for nighttime 

driving.(1) Because there is not a definitive minimum retroreflectivity level required for nighttime driving, this value of 

100 mcd/m2/lx has been used several times throughout this report as a reference point to make comparisons and call out 

important aspects of other research efforts. 

As mentioned previously, another way to determine minimum retroreflectivity levels is to use a visibility metric such as the enddetection distance. FHWA’s ongoing efforts to revise the MUTCD to add minimum retroreflectivity levels for pavement markings 

are based on a combination of approaches. The proposed minimum retroreflectivity levels were modeled using a combination 

of physics associated with retroreflectivity and results from related human factors studies.(28) The FHWA-proposed minimum 

maintained retroreflectivity levels are visibility derived—in other words, they specify the retroreflectivity that is needed under 

specific situations to maintain a specified amount of preview time. There is a belief that visibility performance is a reasonable 

surrogate for safety. 

SUMMARY: Pavement marking detection distance provides an objective way to measure pavement marking visibility, 

although it may not be directly tied to a specific driving task. Subjective studies and visibility modeling have been used to 

determine visibility-derived recommendations for minimum maintained retroreflectivity levels. If additional research is 

performed in this area, it should include objective human factors testing with an aim to derive replacement retroreflectivity 

levels based on nighttime driver needs.
June 2015 | Chapter 4: Dry Pavement Marking Retroreflectivity

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

SAFETY

Similar to pavement marking width, pavement marking retroreflectivity and its effect on nighttime crashes has been studied 

for years. There is a general belief that a positive relationship exists, but researchers have not been able to fully describe it. The 

amount and quality of retroreflectivity data have been increasing, however, because mobile retroreflectometers have become 

more prevalent. Some agencies have been collecting system data periodically for nearly a decade, providing researchers more 

opportunity to discover the impacts of retroreflectivity on safety. 

In 2006, researchers in New Zealand studied the safety impacts of brighter pavement markings and reported that there was not a 

conclusive improvement in safety.(30) This study took advantage of a 1997 policy change in New Zealand that required a minimum 

maintained retroreflectivity level of 70 mcd/m2/lx. Using a before-and-after approach, the authors compared crash rates before 

the change in policy. One assumption of the study was that markings were brighter during the after period. These results may 

not be directly applicable to the United States, since in New Zealand roadways are delineated as a function of traffic volume. 

As volumes increase, they progressively apply the following treatments: delineators, center lines, edge lines, and then raised 

retroreflective pavement markers (RRPMs). Roadways with center lines also have delineators. As a side note, research has shown 

that supplemental delineation treatments, such as delineators or RRPMs, overpower the potential effect of pavement markings.(31)

Also in 2006, the results of a National Cooperative Highway Research Program (NCHRP) study concluded: “...the difference in 

safety between new markings and old markings during non-daylight conditions on non-intersection locations is approximately 

zero.”(32) This finding has been discussed and debated for years, and continues to fuel debate in the highway safety space. A close 

evaluation of the study reveals several points that are worth noting: 

• While the study incorporated large amounts of crash data and used contemporary statistical techniques, there were 

limitations. For instance, the research only included crashes from California and modeled retroreflectivity 

(no measurements were made). 

• While the study included efforts to overcome the possible limitations in modeling retroreflectivity, these efforts 

presupposed that markings in California reach a value where there is an adverse impact on safety. 

• The pavement marking maintenance policy of California is such that higher volume highways are restriped up to 

three times a year with paint or every two years with thermoplastic markings. As a result, there is only the occasional 

roadway with retroreflectivity levels below 100 mcd/m2/lx (in other words, most markings were adequate for 

nighttime driving).

In addition to the concerns regarding the modeled retroreflectivity levels, the researchers binned the retroreflectivity levels in 

bins divided in a linear fashion. The lowest bins for the edge lines included retroreflectivity levels from 21 to 183 mcd/m2

/lx, thus 

including markings ranging from inadequate to adequate in the same bin (according to a synthesis of perception studies reported 

elsewhere(35)). Eight additional bins included retroreflectivity levels up to 413 mcd/m2/lx. It might have been more productive to 

form the bins in a logarithmic function since the performance of retroreflectivity has been repeatedly shown to be best modeled 

logarithmically rather than linearly.(33,34)

In 2007, researchers reported results from an effort using North Carolina that aimed to develop a statistical association between 

measured pavement marking retroreflectivity and traffic crash frequency.(36) The results suggest that increased levels of the 

average pavement marking retroreflectivity on multilane highways may be associated with lower expected target crash 

frequencies. However, the association was small in magnitude and not statistically significant. On two-lane highways, the 

association between pavement marking retroreflectivity and crash frequency was larger in magnitude and marginally significant. 

The retroreflectivity levels used in this study were above 100 mcd/m2/lx with an overall average of 240 mcd/m2/lx.

10
11

 Chapter 4: Dry Pavement Marking Retroreflectivity | June 2015 

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

In 2008, a similar effort in Iowa included three years of measured retroreflectivity.(37) These data were analyzed along with crash 

records from the same year. The distributions and models of the entire database, and a subset including only two-lane highways, 

did not show that pavement marking retroreflectivity correlated to crash probability. Truncating the data to only records with 

retroreflectivity values less than 200 mcd/m2

/lx revealed a statistically significant relationship.

In 2010, researchers in Iowa expanded their effort to study the statistical relationship between crashes and longitudinal pavement 

marking retroreflectivity.(38) While this effort included five years of retroreflectivity data, it was only on certain segments—the crash 

data set included 1,343 records, which constitutes approximately 1.6 percent of all records statewide. This small sample size was 

noted as a challenge for the statistical analyses, since the occurrence is a rare event within the whole data set. Retroreflectivity was 

found to be a significant parameter in the probability of crash occurrence when only data from the interstate roads were analyzed 

and when the data were divided into three subsets by line type (white edge lines, yellow edge lines, and yellow center lines). In 

the final set of analyses for white edge lines and yellow center lines, crash occurrence probability was found to increase when 

longitudinal pavement marking retroreflectivity decreased. While the extent of the study and the data set are not sufficient to 

identify a definitive relationship, the researchers noted that the results represent a potential relationship that supports additional 

analyses to link pavement marking retroreflectivity and highway safety through crashes. 

Another study on the relationship between retroreflectivity and safety was published in 2013.(39) Using data from Michigan, the 

researchers evaluated relationships between crashes and longitudinal pavement marking retroreflectivity. The retroreflectivity 

data consisted of pavement marking measurements representing white edge lines, white lane lines, yellow edge lines, and yellow 

center lines. The data included crashes and retroreflectivity measurements from 2002 to 2008. 

This study only considered nighttime crashes that occurred under dry conditions at non-intersection and non-interchange 

segments from April through October. The following specific types of crashes were initially identified as target crashes for 

this study: 

• Nighttime.

• Single-vehicle nighttime. 

• Fatal plus injury nighttime.

• Single-vehicle nighttime fatal plus injury. 

The results were different for yellow center line and white edge lines:

• The effect of retroreflectivity of the yellow center lines on nighttime crashes and single-vehicle nighttime crashes 

with low retroreflectivity (≤150 mcd/m2/lx) was found to be statistically significant. The results suggest that expected 

crash frequency decreases as the center line retroreflectivity increases, specifically in the low range (≤150 mcd/m2/lx). 

• The retroreflectivity for white edge lines was found statistically significant for nighttime crashes and single-vehicle 

nighttime crashes. The results suggest that the expected crash frequency decreases as the white edge line 

retroreflectivity increases.

The findings lend support to the positive safety effects of maintaining the retroreflectivity of pavement markings. There 

was no attempt to develop or validate thresholds of retroreflectivity; however, the findings do provide compelling evidence 

demonstrating that maintenance of pavement marking retroreflectivity can have a positive effect on safety.

A follow-up analysis of the Michigan data was presented in 2014 with a focus on how the combined associations of edge line and 

center line retroreflectivity levels relate to nighttime crashes on two-lane rural highways.(40) This study included only two-lane 

highways (no freeways) and only actual retroreflectivity readings (no imputed retroreflectivity records). 
12

June 2015 | Chapter 4: Dry Pavement Marking Retroreflectivity

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

The results of this follow-up work continue to provide evidence that the retroreflectivity of pavement markings relates to safety 

(this time for two-lane highways in Michigan). In particular, this analysis found that the retroreflectivities of both white edge and 

yellow center lines jointly contribute to the relationship between nighttime crashes. The relationship was captured by 

two parameters:

• The sum of the edge line and the center line retroreflectivities.

• The difference of retroreflectivity values (i.e., white–yellow).

The sum of retroreflectivities was found to relate to nighttime crashes in inverse proportion. Conversely, the difference of 

retroreflectivities was found to relate to night crash frequency in direct proportion. In other words, sites with brighter pavement 

markings tend to have fewer nighttime crashes. 

A follow-up paper published in 2015 builds from the retroreflectivity-safety analysis.(41) Data from North Carolina were obtained 

and used to continue to evaluate how pavement marking retroreflectivity relates to nighttime safety on rural two-lane 

highways. The North Carolina data were used to test the robustness of the statistical models derived from the Michigan data. 

Additional analyses were also explored and described. Using the results from this paper, previous research, and the state of 

the practice, recommendations and their implications were developed for safety-derived minimum retroreflectivity levels 

for pavement markings. 

SUMMARY: The relationship between pavement marking retroreflectivity and safety has proven elusive. As more data are 

becoming available, research is beginning to show consistent findings regarding the positive relation between retroreflectivity 

and nighttime crashes. The research findings described in this section provide consistent evidence that specifying and 

maintaining adequate pavement marking retroreflectivity can increase safety. However, additional research could potentially 

strengthen the understanding of how specific retroreflectivity levels impact nighttime safety. 

TEST METHODS AND SPECIFICATIONS

The current test method for measuring retroreflectivity under dry conditions is ASTM E1710. This test method states that 

equipment used to measure pavement marking retroreflectivity has to meet certain criteria, such as having a measurement 

geometry of 30 meters. ASTM E1710 is written for handheld measurement equipment and includes a precision and bias 

statement to provide users an indication of the errors associated with such measurements. 

While various types of mobile measurement equipment are being used around the United States, there is no national 

specification for mobile equipment. The Texas Department of Transportation currently requires that all users of mobile 

retroreflectivity equipment have their equipment and operators certified on an annual basis. 

The most common specifications for pavement markings include American Association of State Highway and Transportation 

Officials (AASHTO) M247, which describes most beads used for pavement markings. In addition, ASTM D7585 includes sampling 

procedures for inspection of pavement marking retroreflectivity.

A performance-based specification for thermoplastic markings is under development within ASTM D04.38. Discussions have 

been held to initiate a more comprehensive performance-based specification within ASTM, but the work has not yet started. 

There is no national model for a performance-based pavement marking specification. 
13

 Chapter 5: Wet Pavement Marking Retroreflectivity | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 5: Wet Pavement Marking Retroreflectivity

The interest in pavement marking performance during wet nighttime conditions has increased in recent years. Research on wet 

retroreflective pavement marking performance was practically nonexistent a decade ago, but more recently a number of efforts 

have sought to better understand wet retroreflective pavement marking performance. Much of the research is related to visibility 

gains in wet nighttime conditions and the durability of marking performance in wet nighttime conditions. The potential safety 

benefits of wet pavement marking retroreflectivity is a topic of recent interest but to date there has not been an established 

relationship. There are also concerns that increased visibility of markings in wet conditions could potentially result in more drivers 

going too fast for the wet conditions. 

OPERATIONAL PERFORMANCE 

In 2013, research documented findings related to speed and lateral placement in active highway work zones, with pavement 

markings designed to have high-performing wet nighttime retroreflectivity levels. Five test sites were selected in North Carolina 

and Ohio. The researchers used the vehicle travel speed, rate of lane encroachment, and linear lane displacement to evaluate 

the effectiveness of the markings. The initial retroreflectivity of the prototype markings was higher than that of comparable 

markings, but not consistently higher. These findings produced inconclusive results, similar to the results from dry retroreflectivity 

studies.(42)

SUMMARY: Like dry pavement marking retroreflectivity performance, wet pavement marking retroreflectivity performance 

has not been shown to impact operational measures of performance such as vehicle speed or lateral placement. If 

additional research is performed in this area, it should include new considerations (e.g., the benefits of retroreflectivity 

during wet conditions and when driving can be particularly challenging, such as on undivided highways with opposing 

vehicle headlamp glare). 

VISIBILITY

Early studies of wet nighttime pavement marking performance were conducted with the retroreflectivity measurements based 

on ASTM E2176, which required almost 10 inches of water per hour on the markings during measurements. The more recent 

studies summarized here have used the superseding test method, ASTM E2832, which is based on 2 inches of water per hour 

during measurements. 

Several significant studies have involved the performance and visibility of pavement markings in wet conditions. One of the 

initial key studies was conducted in Texas in 2007. This study included visibility measurements of 18 different pavement markings 

in an intensity-controlled rain tunnel, where participants drove through simulated rain looking for randomly positioned lane line 

markings.(12) The results show that wet retroreflectivity cannot be predicted by dry retroreflectivity. In general, dry retroreflectivity 

is typically higher than wet retroreflectivity. The study of retroreflectivity, and particularly wet retroreflectivity, is very dependent 

on the characteristics of the pavement marking materials. 

The researchers formatted the results in terms of preview times provided by various pavement markings (and RRPMs). The study 

produced results showing that pavement markings, even those specifically designed for wet nighttime performance, are not a 

replacement for RRPMs in terms of visibility and cost of visibility per mile. The costs of the RRPMs were based on surface-applied 

RRPMs, which are mostly used in areas with no or very little snow plow operations. This study did not include any aspect of 

durability. All of the markings used were performing as if they were newly installed. 
14

June 2015 | Chapter 5: Wet Pavement Marking Retroreflectivity

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

In 2009, researchers reported an evaluation of pavement marking performance using specially designed optics for wet nighttime 

visibility. This study included three prototype optics-on-paint marking systems employing high-refractive-index, dual-optics, 

drop-on elements.(43) These markings were evaluated at night under dry, wet-recovery, and continuous wetting conditions. 

Two commercially available marking systems (one glass beads-on-paint system and one wet-reflective removable tape) were 

also evaluated as industry benchmarks. Thirty participants driving through simulated work zones on a closed course viewed all 

of the marking types at night under all three weather conditions. Each driver’s task was to identify the direction of work zone 

lane shift tapers delineated by the markings. In wet recovery, all three prototype marking systems and the wet-reflective tape 

sustained 60 to 80 percent of their dry average detection distances. In rain, they sustained 50 to 70 percent of their dry average 

detection distances. In contrast, the average wet-recovery and rain detection distances for the conventional glass beads-on-paint 

benchmark system dropped to 28 and 17 percent of the dry detection distance, respectively. In addition, participants failed to 

detect the conventional glass beads-on-paint benchmark system in nearly half of the observations in the rain condition.

A 2012 Virginia study evaluated the detection distance of several pavement marking types in wet conditions.(22) The 

markings were surface applied, recessed, and installed over a rumble strip (often called a rumble stripe). While there were 

differences among the pavement marking products studied, the wet nighttime performance of the markings degraded to 

100 mcd/m2/lx or less after the first year. The research team was able to derive a minimum required level for wet nighttime 

retroreflectivity of 150 mcd/m2/lx. This level was based on their data and assumptions about how much preview time is needed 

for safe nighttime driving. 

SUMMARY: The dry retroreflectivity performance of a marking does not indicate how the marking will perform under 

wet conditions. In general, dry retroreflectivity is almost always higher than wet retroreflectivity. The wet retroreflectivity 

performance is very dependent on the pavement marking optic materials. Additional research will be needed to validate 

appropriate research recommendations for minimum wet nighttime retroreflectivity. Additional research is also needed to 

understand how wet retroreflective pavement marking visibility affects nighttime crashes. 

DURABILITY

As noted in the previous section, the durability of wet nighttime pavement marking performance has been reported to be 

relatively short, at least compared to dry pavement marking performance. This is an area where research is just starting to 

emerge, although several evaluations are currently underway and more results are expected soon. 

In Iowa, research was performed in 2011 on 16 variations of pavement markings over a two-year period to assess their 

performance and durability in wet conditions.(44) The study included yellow edge line and white lane line markings that were 

both surface applied and recessed. They were measured under dry and wet conditions over a period including two winters. 

The research found that:

• For the yellow edge line markings, the initial wet retroreflectivity measurements showed that only 7 of the 16 sections 

measured above 100 mcd/m2/lx. After one winter, only three sections measured above 100 mcd/m2/lx. (Again, the 

performance of these sections is very dependent on the materials used and the application techniques.) After two 

winters, only two sections measured above 100 mcd/m2/lx.

• For the white lane line markings, the initial wet retroreflectivity measurements showed that 13 of the 16 sections 

measured above 100 mcd/m2/lx. After one winter, six sections measured above 100 mcd/m2/lx (and all of these 

were grooved). After two winters, only one section measured above 100 mcd/m2/lx. 

• The results indicate that placing markings in a groove can protect them from plowing operations. 
15

 Chapter 5: Wet Pavement Marking Retroreflectivity | June 2015 

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

SUMMARY: Markings that provide long-lasting wet retroreflectivity performance are not yet widely available. Even with 

a new, more controlled ASTM test method for measuring the performance of pavement markings under a continuous 

condition of wetting, there are some concerns that the durability of markings designed specifically for wet nighttime 

visibility is too short. Placing markings in a groove can help maintain an adequate performance level in areas with snow 

plowing operations. 

TEST METHODS AND SPECIFICATIONS

In the United States, there are two test methods for measuring wet retroreflectivity:

• ASTM E2177. This test method measures pavement markings in a condition of wetness but not actually being wetted. 

This test method represents how quickly a pavement marking can recover from the rain.

• ASTM E2832. This test method measures how well markings can perform under a standard condition of wetting (i.e., 

representing rain conditions). This supersedes ASTM E2176.

Both of these test methods were designed around handheld measurement equipment. Both test methods include a precision 

and bias statement to provide users an indication of the errors associated with such measurements. There are still some concerns 

about the repeatability of the test method for continuous wetting.
16

June 2015 | Chapter 6: Combined Impacts of Markers

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 6: Combined Impacts of Markers

Pavement markings are intended to provide the road user an indication of lane position and roadway alignment. Under wet 

nighttime conditions, many traditional pavement markings lose much—if not all—of their retroreflective performance. As noted 

in the previous chapter, significant progress has been made in terms of developing pavement markings that maintain their dry 

retroreflectivity performance in various conditions of wetting. However, the traditional way to provide wet nighttime visibility 

is the use of RRPMs. Research efforts have been undertaken to understand the durability of RRPMs, but little research has been 

conducted to understand how the performance of RRPMs and pavement markings can be combined. 

One of the most recent studies was a multi-phase study commissioned by the FHWA that focused on understanding the 

combined impacts of center line and edge line pavement marking retroreflectivity and pavement markers.(45, 46, 47) The initial 

focus of this effort was to determine how the presence of markers might impact the need for various pavement marking 

retroreflectivity levels. 

The first part of the study, published in 2003, consisted of a simulator study designed to address the question, “How much can 

the retroreflectivity of roadway pavement markings be reduced if raised pavement markers of a certain retroreflectivity are 

installed on the road?” The researchers discussed the concept of a trading ratio, which refers to trading off the retroreflectivity 

of markings with the installation of markers. Curve recognition distance was used to determine the trading ratio of markers to 

marking condition.(45) The study concluded that the trading ratio was 0.55 for yellow center lines on non-freeway roads, which 

means pavement markings could degrade as much as 45 percent with the addition of pavement markers and still maintain the 

same overall curve detection distances.

A second simulator experiment, published in 2004, investigated the interaction between center line and edge line luminance 

on driver curve recognition distances.(46) Just as the addition of pavement markers increases road delineation luminance, 

the addition of edge lines to center lines also increases the delineation luminance. In a parallel to their previous experiment, 

the researchers looked for the trading ratio for the addition of edge lines that would allow for degradation in center line 

retroreflectivity while maintaining the same curve detection distance. The researchers calculated the trading ratio between 

center lines and edge lines to be 0.41, which means center line luminance may be allowed to degrade by as much as 59 percent 

with the addition of edge lines, while maintaining the same curve detection distances.

The limited contrasts available with their simulator in both simulator experiments were 150:1, which is “far below those likely 

to be experienced on a real roadway at night.” This limitation in contrast emphasized the need for a field validation study. The 

researchers conducted the field validation of the two previous experiments.(47) The field study was conducted on a newly 

constructed highway, not opened to other traffic, and delineated to look like a two-lane rural highway; 12-foot wide lanes 

matched the lanes used in the two previous simulator studies. The road grade was a constant 0.84 percent downhill, and there 

was no illumination by fixed roadway lighting. The closed road did have some ambient illumination from nearby buildings and 

other roads. Six trials were conducted, which took about nine hours per participant over seven nights.

The field validation called into question the use of simulators for pavement marking studies. The researchers found that, 

because of the limited contrast ratios simulators can project, simulators are poor representations of real-world conditions. The 

researchers revised the previous simulator findings to say that their trading ratios between center line markers and markings 

are valid only for markers that are very faded or have low retroreflectivity. In the field, pavement markers were so much brighter 

than the pavement markings that they produced trading ratios that were practically zero (less than 0.001). In other words, the 

effect of pavement markers is so much more powerful than pavement markings in curve detection distances that yellow center 

lines could be allowed to deteriorate by more than 99 percent in retroreflectivity if new pavement markers were added. The 

researchers therefore questioned the concept of a trading ratio in providing useful engineering information. In general, the issue 
17

 Chapter 6: Combined Impacts of Markers | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

of “trading” the retroreflectance of longitudinal lines with lines that have pavement markers is not entirely resolved or agreed 

upon by the research community. Findings from the second simulator study were validated in that low-luminance edge lines 

combined with low-luminance center lines produced higher curve detection distances than low-luminance center lines alone.

Also in 2004, an NCHRP report was published focusing on the safety effectiveness of snowplowable raised pavement markers 

on two-lane and four-lane highways.(48) Crash prediction models were developed for various crash types: total, fatal and injury, 

nighttime, nighttime fatal and injury, daytime, daytime fatal and injury, wet weather, dry weather, and guidance-related. Using 

data from four northern States, the authors discovered that nonselective use of raised pavement markers on two-lane roadways, 

overall, does not significantly reduce total or nighttime crashes, nor does it significantly increase these crash types. Mixed 

results were discovered for selective use (e.g., poor crash history) of raised pavement markers on two-lane roadways. On fourlane freeways, the use of raised pavement markers showed neither a positive nor a negative overall safety effect on total and 

nighttime crashes. However, some significant reductions were recorded for wet weather crashes at those locations on four-lane 

freeways, and there are indications that they are only effective in reducing nighttime crashes where the AADT exceeds 

20,000 veh/day.

In 2011, researchers measured luminance (instead of retroreflectivity) to assess the visibility of various delineation treatments 

including pavement markings and markers. To assess their performance, the visibility level was used instead of retroreflectivity. 

This metric allows the results to be normalized for direct comparison. It can also provide an indication of the impacts of 

continuous versus intermittent delineation.(49) An example of the results is shown in Figure 2. 

 Figure 2. Bar chart. Comparison of visibility by delineation type.(46)
18

June 2015 | Chapter 6: Combined Impacts of Markers

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

In this example, the markings were applied within the week prior to the measurements using low volatile organic compound 

paint and Type I AASHTO M247 beads. The RRPMs were non-plowable and were installed in a 0.5-inch deep groove according 

to the contract specification. The guardrail delineator tabs were the butterfly variety and were seven years old. The results 

demonstrate the added value of RRPMs for wet nighttime conditions. They also provide some evidence that performance 

metrics other than retroreflectivity can lead to better understanding the impacts of various delineation treatments such as 

pavement markings. 

SUMMARY: The use of simulators to study the combined impacts of center line and edge line pavement marking 

retroreflectivity and pavement markers did not result in definitive findings. Additional work from the field suggests that 

visibility metrics other than retroreflectivity may be more useful to better understand how various delineation treatments 

perform in terms of providing visibility. Overall, the use of snowplowable markers has been shown to have mostly negligible 

impact (positive or negative) on nighttime safety. An NCHRP research project is currently being planned that is designed to 

develop enhanced RRPM recommendations (NCHRP Project 05-21). 
19

 Chapter 7: Pavement Marking Selection Tools | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 7. Pavement Marking Selection Tools

Research has produced various pavement marking material selection tools.(See references 50 through 55) These studies were generally 

conducted at the State level and produced recommended marking materials using a matrix of factors. Criteria for marking 

material selection in the various reports included traffic volume, road surface, environmental conditions, remaining expected 

road surface life, placement of new markings vs. restriping existing markings, costs, and location of marking. 

An FHWA study nearing completion has the goal of developing a pavement marking selection tool to aid in selecting the most 

appropriate material for a given situation.(50) The report and tool are expected to provide a more effective and uniform guide to 

select pavement marking material. The tool was designed to take user inputs, perform service life and cost analysis, and then 

provide recommendations for selecting pavement marking materials. The tool has retroreflectivity degradation factors based on 

pavement marking test deck data from the National Transportation Product Evaluation Program and other sources in 

the literature.

The computational procedure of the tool consists of the following steps:

1. A user enters site characteristics, cost data, and material choices for the analysis.

2. A computational engine selects initial retroreflectivity models that fit the site characteristics to estimate initial 

retroreflectivity values for all the material options. The computed values use the default initial values unless a 

user provides specific initial values instead.

3. A computational engine selects bi-exponential decay models that fit the site characteristics to estimate the expected 

service life for each material choice. The expected service life is defined as the time that it takes for the pavement 

marking retroreflectivity to reach the specified minimum retroreflectivity values. A Solver add-in in Microsoft® Excel® 

is used to perform this analysis.

4. A computational engine performs cost analysis for each material to estimate the expected unit cost over the 

remaining road surface life. 

5. A computational engine ranks the material by cost within the given constraints. The tool provides the top two costeffective materials as recommended options.

Figure 3 shows the results screen, which provides the top two materials based on the life cycle cost analysis, given the project 

characteristics and constraints. Each recommendation includes the expected unit cost of material, expected project cost, annual 

life-cycle cost, and expected service life of the recommended material.

Recommended Materials

Suggested Marking Material #1 Waterborne Paint

Expected Unit cost ($/ft) $ 0.200

Expected Project Cost ($/job) $ 5,280

Life Cycle Cost ($/yr) $2,377

Expected Service Life (months) 28

Suggested Marking Material #2 High Build Paint

Expected Unit cost ($/ft) $ 0.360

Expected Project Cost ($/job) $ 9,504

Life Cycle Cost ($/yr) $4,278

Expected Service Life (months) 29

Figure 3. Screenshot. Results screen. (50)

SUMMARY: Based on the amount of available research on this topic, it is clear that agencies are looking for assistance to 

select the most appropriate pavement marking materials. The ongoing work described in this chapter provides the most 

recent and comprehensive pavement marking selection tool. Once the ongoing work is completed and vetted, it will be clear 

if more work is needed.
20

June 2015 | Chapter 8: Future of Pavement Markings

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 8. Future of Pavement Markings

The most commonly known ongoing work related to pavement markings is the FHWA effort to develop national standards for 

minimum maintained pavement marking retroreflectivity levels for the MUTCD. In addition, there is interest to determine crash 

modification factors associated with pavement marking retroreflectivity levels. As connected vehicle and automated vehicle 

applications and technologies are deployed over the next decade or two, the potential to significantly improve vehicle safety 

may depend on the use of enhanced or innovative pavement markings. 

Connected vehicles are currently one of the main areas of focus of the U.S. Department of Transportation’s Intelligent 

Transportation Systems Joint Program Office (JPO). Connected vehicle safety applications will enable drivers to have 360-degree 

awareness of hazards and situations they cannot even see. Through in-car warnings, drivers will be alerted to imminent crash 

situations, such as unintended lane departures, unintended run off the roadway situations, or when a vehicle ahead brakes 

suddenly. By communicating with enhanced or innovative infrastructure such as pavement markings, drivers will be alerted to 

potential safety, operational and environment vulnerabilities well in advance, helping them to eliminate or mitigate potentially 

hazardous situations. 

Vehicle manufacturers such as General Motors have reported to Congress that pavement markings are one of the most 

significant infrastructure elements needed to guide automated vehicles and realize the estimated safety benefits of such 

vehicles. Knowing that pavement marking is one of the key highway elements used to guide automated vehicles, work is 

needed to better understand how to quantify characteristics and interactions between onboard sensors and pavement 

markings so that they will be detectable by the vehicle system in as many conditions as possible—that is, rain, low sun, high 

glare, and fog. The variety of contrast enhancements used for pavement markings also need to be evaluated—determining 

how the vehicle systems will read these markings, which are intended to improve human vision but may not be as beneficial 

for machine vision. Non-reflective raised pavement markers and profiled markings are also of interest.

Another issue of interest is adding more technology to markings to increase their usefulness, such as magnetic markings or 

markings with Quick Response (QR) codes or radio frequency identification (RFID) tags. These enhanced markings could be 

used in strategic areas such as in advance of horizontal curves. Vehicles could read these enhanced markings and compute 

safe speeds for the specific vehicle and specific roadway conditions (as opposed to one advisory speed that does not adapt to 

vehicles or roadway conditions). 

One more area that looks potentially promising is solar roads and digital pavement markings.(56)
21

 Section 9: Other Topics of Interest | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

CHAPTER 9. Other Topics of Interest 

Other topics that are of possible interest but that are not included in this report are:

• Optics. Optics include glass beads and other types of retroreflective optics. NCHRP Report 743 describes a test 

method that can be used to assess the initial quality of Type I beads, but it is not a field test. Field tests are needed. 

There is also a need to look at some of the specified characteristics of markings—for instance, bead roundness 

is a specification within M247 , but it seems the specification was written around the distribution of roundness 

that is typically produced from the process of using recycled glass. Data exist that demonstrate the rounder the 

glass, the better the retroreflectivity. Other characteristics of M247 should also be reconsidered. In addition, there 

are characteristics of beads that are not addressed in M247 or elsewhere that are known to impact retroreflective 

performance, such as inclusions and crazing. 

• Coatings. Various coatings are used on glass beads to prevent clogging, encourage wicking, and change buoyancy 

for embedment. There is very limited knowledge in the public domain concerning the effectiveness of these 

coatings. Field tests would be very useful for inspectors. 

• Binder. There is a need to determine what types of innovative binders are available to promote durability and 

bead retention. 

• Texturing. A variety of texturing techniques are used for markings for various reasons. The effectiveness of the 

texturing has not been studied. 

• Contrast markings. There are a variety of ways to add contrast to markings. There is no uniformity across the United 

States, and there has been little study of the effectiveness of contrast markings. 

• Color. It has been over a decade since NCHRP Report 484 documented the feasibility of having the United States go 

to an all-white pavement marking system. The environmental reasons driving the effort have since been resolved, 

and there seems to be little interest in moving toward an all-white system. However, white markings typically have 

higher initial and maintained retroreflectivity levels.

• Eye tracking. Recent research shows that markings are the focus of unfamiliar drivers as they negotiate horizontal 

curves, even when there are other in-curve devices present such as chevrons; however, the research was not able to 

quantify the value of markings due to limited resources. There appears to be promise in using eye trackers to help 

better understand how drivers use markings to maintain their lane position and prepare for upcoming roadway 

features such as curves. 

• Heavy metals in glass beads. While this was an issue a couple of years ago, legislation has passed to place limits 

on heavy metals. The issue seems to have faded. 

• Measurements of retroreflectivity. Measuring pavement marking retroreflectivity on profiled markings, 

rumble stripes, and open-graded and large-aggregate surfaces continues to be a challenge. Wet retroreflectivity 

measurements are also an issue since they typically require traffic control, which limits their use in specifications.

• Specifications. There is some momentum among agencies to move toward a performance-based specification 

rather than a method-based specification. In a performance-based specification, an agency specifies the minimum 

retroreflectivity it desires, initially and/or over a specified period (such as a year or more). 

• Photoluminescent markings. In early 2014, a demonstration project in the Netherlands featured photoluminescent 

edge line markings. While the demonstration project was popular on social media, little technical information 

has been released about the markings, such as how the brightness is maintained throughout the night, whether 

photoluminescence works in wet conditions, and what colors are available besides radioactive green. Additional work 

is needed to determine the feasibility of photoluminescent markings. 
22

June 2015 | References

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

References

1. Carlson, P. J., E. S. Park, and C. K. Andersen. “The Benefits of Pavement Markings: A Renewed Perspective Based on Recent and 

Ongoing Research.” Transportation Research Record, No. 1877, 2004, pp. 38–49. 

2. Musick, J. V. “Effect of Pavement Edge Marking on Two-Lane Rural State Highways in Ohio.” Highway Research Board Bulletin 266, 

1962, pp. 1–7.

3. Basile, A. J. “Effect of Pavement Edge Markings on Traffic Accidents in Kansas.” Highway Research Board Bulletin 308, 1962, pp. 

80–86.

4. Secretary of Transportation. The 1981 Highway Safety Stewardship Report. Report to the United States Congress, Office of Highway 

Safety, Federal Highway Administration, U.S. Department of Transportation, Washington, D.C., April 1981. 

5. Missouri Department of Transportation. “White Paper on Edgeline Stripes on Routes with 400–1000 AADT.” January 2013. 

6. Carlson, P. J., E. S. Park, A. M. Pike, R. J. Porter, J. Miles, B. Boulanger, O. Smadi, N. Hawkins, S. Chalmers, F. Darmiento, A. Burde, B. Kuhn, 

and W. Ealding. Pavement Marking Demonstration Projects: State of Alaska and State of Tennessee. FHWA-HRT-12-048, Federal 

Highway Administration, Washington, D.C., November 2013.

7. Gates, T. J., and G. H. Hawkins. The Use of Wider Longitudinal Pavement Markings. Report 0024-1, Texas Transportation Institute, 

College Station, Texas, 2002. 

8. Zwahlen, H. T., and T. Schnell, “Visibility of New Pavement Markings at Night under Low-Beam Illumination.” Transportation Research 

Record, No. 1495, 1995, pp. 117–127. 

9. Ward, A. M. “Sighting Safety.” In Proceedings of the Conference Effectiveness of Highway Safety Improvements, American Society of 

Civil Engineers, New York, New York, 1985.

10. European Commission Directorate-General for Transport. Requirements for Road Marking: State of the Art. Report No. COST331, 

European Cooperation in the Field of Scientific and Technical Research, May 1999.

11. P. Ohme. Enhancing Nighttime Pavement Marking Visibility for Older Drivers. Human Factors and Ergonomics Society, Iowa City, 

Iowa, 2001.

12. Carlson, P. J., J. Miles, A. M. Pike, and E. S. Park. Evaluation of Wet-Weather and Contrast Pavement Marking Applications: Final Report. 

FHWA/TX-05/0-5008-2, Texas Transportation Institute, College Station, Texas, March 2007.

13. Gibbons, R. B., M. J. McElheny, and C. J. Edwards. “The Impact of Pavement Marking Width on Visibility Distance.” Paper #06-1859, 

National Academy of Sciences, Transportation Research Board, Washington, D.C., 2006.

14. Pietrucha, M. T., R. S. Hostetter, L. Staplin, and M. Obermeyer. Pavement Markings and Delineations for Older Drivers. FHWARD-94-145, Federal Highway Administration, Washington, D.C., 1996.

15. Carlson, P., E. S. Park, A. M. Pike, R. J. Porter, J. Miles, O. Smadi, and W. Ealding. Pavement Marking Demonstration Projects: State of 

Alaska and State of Tennessee. FHWA-HRT-09-039, Federal Highway Administration, McLean, Virginia, 2010. 

16. Miles, J., P. J. Carlson, R. Eurek, J. Re, and E. S. Park. Evaluation of Potential Benefits of Wider and Brighter Edge Line Pavement 

Markings. Report 0-5862, College Station, Texas, 2010.

17. Cottrell, B. H. Evaluation of Wide Edge Lines on Two-Lane Rural Roads. FHWA-VA-85-37, Virginia Highway and Transportation 

Research Council, Virginia Department of Transportation, Richmond, Virginia, 1987.

18. Cottrell, B. H. “Evaluation of Wide Edge Lines on Two-Lane Rural Roads.” Transportation Research Record, No. 1160, 1988, pp. 35–44. 

19. Hall, J. W. “Evaluation of Wide Edge Lines.” Transportation Research Record, No. 1114, 1987, pp. 21–27.

20. Gibbons, R. B. Pavement Marking Visibility Requirements during Wet Night Conditions. Report VTRC-07-CR7, Virginia Transportation 

Research Council, Charlottesville, Virginia, November 2006.

21. Carlson, P. J., and J. Wagner. An Evaluation of the Effectiveness of Wider Edge Line Pavement Markings. Texas A&M Transportation 

Institute, College Station, Texas, February 2012.

22. Gibbons, R. B., and B. M. Williams. Assessment of the Durability of Wet Night Visible Pavement Markings. VCTIR 12-R13, Blacksburg, 

Virginia, June 2012. 

23. Donnell, E. T., D. Lee, J. Molino, and K. S. Opiela. “Can Pavement Marking Curve Delineation Improve the Consistency of Vehicle 

Speed and Lane Position?: Results from a Nighttime Driving Experiment.” Paper No. 07-0943, Proceedings from Transportation 

Research Board Annual Meeting, Transportation Research Board, Washington, D.C., 2007. 

24. Carlson, P. J., J. D. Miles, A. M. Pike, and E. S. Park. Evaluation of Wet-Weather and Contrast Pavement Marking Applications: Final 

Report. FHWA/TX-05/0-5008-2, Texas Transportation Institute, College Station, Texas, March 2007. 
23

References | June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

25. Higgins, L., J. Miles, P. Carlson, F. Aktan, and D. Burns. “The Nighttime Visibility of Prototype Work Zone Markings under Dry, Wet, 

and Raining Conditions.” Paper No. 09 2043, Submitted to 88th Transportation Research Board Annual Meeting, Washington, D.C., 

January 2009.

26. Aktan, F., and T. Schnell. “Performance Evaluation of Pavement Markings under Dry, Wet, and Rainy Conditions in the Field.” 

Transportation Research Record, No. 1877, 2004, pp. 38–49. 

27. Finley, M. D., P. J. Carlson, N. D. Trout, and D. L. Jasek. Sign and Pavement Marking Visibility from the Perspective of Commercial 

Vehicle Drivers. Report 0-4269-1, Texas Transportation Institute, College Station, Texas, September 2002. 

28. Deballion, C., P. J. Carlson, Y. He, T. Schnell, and F. Aktan. Updates to Research on Recommended Minimum Levels for Pavement 

Marking Retroreflectivity to Meet Driver Night Visibility Needs. FHWA-HRT-07-059, Federal Highway Administration, U.S. Department 

of Transportation, Washington, D.C., October 2007.

29. Park, E. S., P. J. Carlson, R. J. Porter, and C. K. Andersen. “Safety Effects of Wider Edge Lines on Rural Two-Lane Highways.” Accident 

Analysis and Prevention, Vol. 48, September 2012, pp. 317–325.

30. Dravitzki, V. K., S. M. Wilkie, and T. J. Lester. The Safety Benefits of Brighter Roadmarkings. Land Transport, Wellington, New Zealand, 

2006.

31. Molino, J. A., K. S. Opiela, C. K. Andersen, and M. J. Moyer. “Relative Luminance of Retroreflective Raised Pavement Markers and 

Pavement Marking Stripes on Simulated Rural Two-Lane Roads.” Transportation Research Record, No. 1844, 2003, pp. 45–51. 

32. Bahar, J. M., M. Masliah, T. Erwin, E. Tan, and E. Hauer. Pavement Marking Materials and Markers: Real-World Relationship between 

Retroreflectivity and Safety over Time. NCHRP Web-Only Document 92, April 2006. http://onlinepubs.trb.org/onlinepubs/nchrp/

nchrp_webdoc_92.pdf. 

33. Aktan, F., and T. Schnell. “Performance Evaluation of Pavement Markings under Dry, Wet, and Rainy Conditions in the Field.” 

Transportation Research Record, No. 1877, 2004, pp. 38–49. 

34. Finley, M. D., P. J. Carlson, N. D. Trout, and D. L. Jasek. Sign and Pavement Marking Visibility from the Perspective of Commercial 

Vehicle Drivers. FHWA/TX-03/4269-1, Texas Department of Transportation, Austin, Texas, 2002. 

35. Kopf, J. Reflectivity of Pavement Markings: Analysis of Retroreflectivity Degradation Curves. WA-RD 592.1, Washington State 

Department of Transportation, Olympia, Washington, 2004. 

36. Donnell, E. T., and S. Sathyanarayanan. Exploring the Statistical Association between Pavement Markings Retroreflectivity and Traffic 

Crash Frequency on Two- and Multilane Highways in North Carolina. Pennsylvania State University, University Park, Pennsylvania, 

2007. 

37. Smadi, O., N. R. Hawkins, R. R. Souleyrette, and D. Ormand. “Analysis of Safety Effectiveness of Pavement Marking Retroreflectivity.” 

87th Transportation Research Board Annual Meeting, Washington, D.C., 2008. 

38. Smadi, O., N. Hawkins, I. Nlenanya, and B. Aldemir-Bektas. Pavement Markings and Safety. IHRB Project TR-580, Iowa Highway 

Research Board, Iowa State University, Ames, Iowa, 2010.

39. Carlson, P. J., E. S. Park, and D. H. Kang. “An Investigation of Longitudinal Pavement Marking Retroreflectivity and Safety.” 

Transportation Research Record, Publication Pending. 

40. Avelar, R. E., and P. J. Carlson. “Characterizing the Combined Association of Edge Line and Center Line Retroreflectivity to Nighttime 

Crashes on Michigan Rural Two-Lane Highways.” Transportation Research Record, Publication Pending. 

41. Avelar, R.E., P.J. Carlson, E.S. Park, and D. Kang. Nighttime Safety and Pavement Marking Retroreflectivity on Two-Lane Highways: 

Revisited with North Carolina Data. Washington DC: Transportation Research Record, Annual Meeting. Washington DC, 2015.

42. Cunningham, C. M., J. E. Hummer, J. Chang, D. Katz, C. L. Vaughan, D. J. Findley, B. J. Schroeder, and D. McAvoy. Temporary WetWeather Pavement Markings for Work Zones, Phase II: All-Weather Pavement Marking for Work Zones, Field Evaluation in North 

Carolina and Ohio. FHWA-HIF-13-004, May 2013

43. Higgins, L., J. D. Miles, P. Carlson, D. Burns, F. Aktan, M. Zender and J. M. Kaczmarczik. “Nighttime Visibility of Prototype Work Zone 

Markings under Dry, Wet-Recovery, and Rain Conditions.” Transportation Research Record, No. 2107, 2009, pp. 69–75.

44. Wet-Reflective Pavement Marking Demonstration Project. IHRB Project TR-597, November 2011.

45. Molino, J. A., K. S. Opiela, C. K. Anderson, and M. J. Moyer. “Relative Luminance of Retroreflective Raised Pavement Markers and 

Pavement Marking Strips Rural Two-Lane Roads.” 82nd Transportation Research Board Annual Meeting, Washington, D.C., 2003.

46. Molino, J. A., K. S. Opiela, C. K. Anderson, and M. J. Moyer. “Relative Luminance of Center Line vs. Edge Line Pavement Markings on 

Simulated Rural Two-Lane Roads at Night.” 83rd Transportation Research Board Annual Meeting, Washington, D.C., 2004.
24

June 2015 | References

SYNTHESIS OF PAVEMENT MARKING RESEARCH 

47. Molino, J. A., B. J. Katz, D. A. Duke, K. S. Opiela, C. K. Anderson, and M. J. Moyer. “Field Validation for the Relative Effectiveness 

of Combinations of Pavement Markings and Retroreflectivity Raised Pavement Markers in Recognizing Curves at Night.” 83rd 

Transportation Research Board Annual Meeting, Washington, D.C., 2004.

48. Bahar, G., C. Mollett, B. Persaud, C. Lyon, A. Smiley, T. Smahel, H. McGee. Safety Evaluation of Permanent Raised Pavement Markers. 

NCHRP Report 518. Washington, D.C., 2004. 

49. Nighttime Visibility of In-Service Pavement Markings, Pavement Markers, and Guardrail Delineation in Alaska. FHWA-AK-RD-11-04, 

March 2011.

50. Ullman, G., M. Finley, A. Pike, K. Knapp, P. Songchitruksa, and A. Williams. Studies to Improve Temporary Traffic Control at Urban 

Freeway Interchanges and Pavement Marking Material Selection in Work Zones. Research Report 0-5238-2, Texas Transportation 

Institute, College Station, Texas, March 2008.

51. Dwyer, C., W. Vavrik, and R. Becker. Evaluating Pavement Markings on Portland Cement Concrete (PCC) and Various Asphalt Surfaces: 

Results of Year 1, 2, 3, and 4 Data Collection. Research Report FHWA-ICT-113-033, Applied Research Associates, Champaign, Illinois, 

December 2013.

52. Oregon Department of Transportation. Pavement Marking Design Guidelines. October 2011.

53. Hawkins, H. G., Jr., T. J. Gates, and E. R. Rose. Pavement Marking Handbook. Product 0-4150-P1, Texas Transportation Institute, College 

Station, Texas, 2004.

54. KDOT Pavement Marking Advisory Committee. Pavement Marking Policy. Kansas Department of Transportation, January 2002.

55. Connor, B., and J. Bennett. Selection of Pavement Marking Materials. Research and Technology Transfer, Alaska Department of 

Transportation, 2001.

56. Solar Roadways web page: http://www.solarroadways.com/intro.shtml
25

 June 2015

SYNTHESIS OF PAVEMENT MARKING RESEARCH 
For More Information:

http://www.safety.fhwa.dot.gov

FHWA Office of Safety

Cathy Satterfield

cathy.satterfield@dot.gov

FHWA-SA-15-063