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FHWA Home / Highways for LIFE / Technology Partnerships / Safety-Related Technologies / All-Weather Pavement Marking for Work Zones: Field Evaluation in North Carolina and Ohio

All-Weather Pavement Marking for Work Zones: Field Evaluation in North Carolina and Ohio

TEMPORARY WET-WEATHER PAVEMENT MARKINGS FOR WORK ZONES, PHASE II FINAL REPORT

PUBLICATION NO. FHWA-HIF-13-004
May 2013

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.

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Technical Report Documentation Page

1. Report No.
FHWA-HIF-13-004

2. Government Accession No.

3. Recipient's Catalog No.

4. Title and Subtitle
Temporary Wet-Weather Pavement Markings for Work Zones, Phase II: All-Weather Pavement Marking for Work Zones, Field Evaluation in North Carolina and Ohio

5. Report Date
May 2013

6. Performing Organization Code

7. Author(s)
C.M. Cunningham, J.E. Hummer, J. Chang, D. Katz, C.L. Vaughan, D.J. Findley, B.J. Schroeder, and D. McAvoy

8. Performing Organization Report No.

9. Performing Organization Name and Address
Institute for Transportation Research and Education
North Carolina State University
Centennial Campus Box 8601
Raleigh, NC 27695

10. Work Unit No. (TRAIS)

11. Contract or Grant No.
DTFH61-08-G-00001

12. Sponsoring Agency Name and Address
Federal Highway Administration
Highways for LIFE Program – HIHL-1
1200 New Jersey Avenue, SE
Washington, D.C. 20590

13. Type of Report and Period Covered
Final Report, November 2007-April 2013

14. Sponsoring Agency Code

15. Supplementary Notes

16. Abstract
To address the problem of seemingly invisible pavement markings under nighttime, rainy conditions, 3M developed “All-Weather Paint” (AWP), which uses highly retroreflective elements in combination with latex-based pavement marking installed by highway agencies. Whereas standard pavement markings using waterborne pavement marking and glass beads become harder to see in the rain, the AWP performed well during closed-circuit field tests.

Researchers at North Carolina State University and Ohio University teamed up to conduct tests in active highway work zones. The team defined four measures of effectiveness (MOE) in an attempt to quantify safety performance when comparing the AWP to standard pavement marking materials under real-world driving conditions: retroreflectivity, vehicle travel speed, rate of lane encroachments, and linear lane displacement. Data collection procedures for each MOE are systematically outlined throughout the report.

From the results, the study concluded the following: (1) Retroreflectivity values were confirmed to be higher for AWP when compared to standard pavement markings. However, the AWP retroreflectivity values were inconsistent, likely because of the variation of application methods by pavement marking contractors. (2) Speed was used as a surrogate MOE to evaluate safety performance. It was not clear if an increase or decrease in speed has a positive effect on safety. Results showed that speed generally increased as drivers exited work zone lane shifts for all marking types; however, no consistent finding was noted between the two marking systems in similar curves. (3) The findings for lane encroachments varied throughout the sites. While the first site studied indicated that more lane encroachments occurred at standard pavement marking crossovers, a more robust study at a second site found the results to be statistically insignificant. (4) When assessing lateral lane placement, researchers found statistically significant but varied results. More often than not, motorists maintain safer lane placements when traveling along the AWP delineated lanes.

This report documents Phase II of this project. The Phase I report is available on the FHWA website at: Final Report Phase 1 – Temporary Wet-Weather Pavement Markings for Work Zones.

17. Key Words
Retroreflectivity, pavement markings, work zone safety

18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.

19. Security Classification (of this report)
Unclassified

20. Security Classification (of this page)
Unclassified

21. No. of Pages
63

22. Price


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Reproduction of completed page authorized
SI* (Modern Metric) Conversion Factors
APPROXIMATE CONVERSIONS TO SI UNITS APPROXIMATE CONVERSIONS FROM SI UNITS
Symbol When You Know Multiply By To Find Symbol Symbol When You Know Multiply By To Find Symbol
LENGTH LENGTH
in inches 25.4 millimeters mm mm millimeters 0.039 inches in
ft feet 0.305 meters m m meters 3.28 feet ft
yd yards 0.914 meters m m meters 1.09 yards yd
mi miles 1.61 kilometers km km kilometers 0.621 miles mi
AREA AREA
in2 square inches 645.2 square millimeters mm2 mm2 square millimeters 0.0016 square inches in2
ft2 square feet 0.093 square meters m2 m2 square meters 10.764 square feet ft2
yd2 square yards 0.836 square meters m2 m2 square meters 1.195 square yards yd2
ac acres 0.405 hectares ha ha hectares 2.47 acres ac2
mi2 square miles 2.59 square kilometers km2 km2 square kilometers 0.386 square miles mi2
VOLUME VOLUME
fl oz fluid ounces 29.57 milliliters ml mL milliliters 0.034 fluid ounces fl oz
gal gallons 3.785 liters L L liters 0.264 gallons gal
ft3 cubic feet 0.028 cubic meters m3 m3 cubic meters 35.314 cubic feet ft3
yd3 cubic yards 0.765 cubic meters m3 m3 cubic meters 1.307 cubic yard yd3
NOTE: Volumes greater than 1000 l shall be shown in m3
MASS MASS
oz ounces 28.35 grams g g grams 0.035 ounces oz
lb pounds 0.454 kilograms kg kg kilograms 2.202 pounds lb
T short tons
(2000 lb)
0.907 megagrams Mg Mg (or "t") megagrams
(or "metric ton")
1.103 short tons (2000 lb) T
TEMPERATURE (exact degrees) TEMPERATURE (exact degrees)
°F Fahrenheit 5(F–32)/9 or (F–32)/1.8 Celcius °C °C Celsius 1.8C +32 Fahrenheit °F
ILLUMINATION ILLUMINATION
fc foot–candles 10.76 lux lx lx lux 0.0929 foot–candles fc
fl foot–Lamberts 3.426 candela/m2 cd/m2 cd/m2 candela/m2 0.2919 foot–Lamberts fl
FORCE and PRESSURE or STRESS FORCE and PRESSURE or STRESS
lbf pounds 4.45 newtons N N newtons 0.225 poundforce lbf
lbf/in2 pound per square inch 6.89 kilopascals kPa kPa kilopascals 0.145 poundforce per square inch 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)

Table of Contents

List of Figures

List of Tables

List of Abbreviations
AADT Average Annual Daily Traffic
ANOVA Analysis of Variance
AWP All-Weather Paint
CCTV Closed-Circuit Television
DOT Department of Transportation
FHWA Federal Highway Administration
LIDAR Light Detection and Ranging
MOEMeasure of Effectiveness
NOAANational Oceanic and Atmospheric Administration
RIRefractive Index
RPMRaised Pavement Marker
TIPTransportation Improvement Project

Executive Summary

Traffic crashes cause tens of thousands of deaths every year; thus, highway safety is at the forefront of the decision making process of transportation improvement projects. Traffic-related fatalities and severe crashes top the list and are immediate areas of concern to transportation policy and decision makers. Aside from mistakes made by drivers, the conditions of the road and environment often factor in the motorist decision process. Factors including, but not limited to, weather, lighting, and surface deterioration are examples often considered in the condition of the national highway system. Pavement markings are the focus of this research effort—specifically, improving their retroreflectivity under nighttime rainy conditions, which often hinder motorists’ ability to drive safely, especially in work zones, where quick decisions are often a life-or-death situation. Decreased visibility of lane delineation and lack of situational awareness make navigation through complex work zones potentially unsafe for drivers.

To address the problem of poor visibility of pavement markings under nighttime, rainy conditions, 3M developed “All-Weather Paint” (AWP). AWP utilizes highly retroreflective elements in combination with latex-based pavement marking installed by highway agencies. Whereas standard pavement markings become harder to see in the rain, the AWP performed well during closed-circuit field tests.

Researchers at North Carolina State University and Ohio University teamed up to conduct tests in active highway work zones. Five test sites were selected in North Carolina and Ohio. The team defined four measures of effectiveness (MOE) in an attempt to quantify safety performance when comparing the AWP to standard pavement marking under real-world driving conditions: pavement marking retroreflectivity, vehicle travel speed, rate of lane encroachments, and linear lane displacement. Data collection procedures for each MOE are systematically outlined throughout the report. Basic statistical analyses were performed, and the methodologies are stated herein.

From the results, the study concluded the following:

  • Retroreflectivity values were confirmed to be higher for AWP when compared to standard pavement markings. However, the AWP retroreflectivity values were inconsistent, which was likely due to the variation of application methods by pavement marking contractors.

  • Speed was used as a surrogate MOE to evaluate safety performance. It was not clear if an increase or decrease in speed has a positive effect on safety. Results showed that speed generally increased as drivers exited work zone lane shifts for all pavement marking types; however, no consistent finding was noted between the two marking types in similar curves.

  • The findings for lane encroachments varied throughout the sites. While the first site studied indicated that more lane encroachments occurred at standard pavement marking crossovers, the more robust study of the second site found results to be statistically insignificant.

  • Finally, when assessing lateral lane placement, researchers found statistically significant but varied results. More often than not, motorists maintain safer lane placements when traveling along the AWP delineated lanes.

In summary, this study shows that AWP provides a low-cost, all-weather marking to improve lane visibility and to enhance safety.

Introduction

Pavement markings are a vital tool for safely navigating our nation’s roads. Pavement markings come in many variations, depending on the application. Many of the pavement markings used today are especially difficult to see in the rain, particularly during nighttime hours. One commonly used pavement marking (herein referred to as “standard pavement marking”) uses a latex paint coupled with 1.5 refractive index glass beads that retroreflect light back to the driver. More times than not, this application method is used in temporary installations such as work zones. However, because the marking is hard to see during nighttime rainy conditions, there is concern that drivers may have lane-keeping issues when navigating through active work zones. This poses a hazard to drivers and increases the risk of crashes. Therefore, most States currently supplement the pavement marking application with raised pavement markers to provide a visual cue to the driver on the location of the lane line.

Funded under the Federal Highway Administration (FHWA) “Highways for LIFE” technology partnerships program, this research project aims to test a variation of the latex-based pavement marking that uses specially designed optical elements for temporary applications such as work zones. Developed by 3M, the “All-Weather Pavement marking” (AWP) consists of a standard pavement marking supplemented with additional optical elements that retroreflect light in rain conditions, greatly increasing visibility during rain events.

Phase I of this study involved testing in a controlled environment. First, 24 pavement marking samples were installed on a test deck in New Orleans, LA, and time-series data regarding their retained retroreflective properties were collected. Three prototype all-weathering markings were identified to carry into the next task, which involved the installation of the pavement markings at the Texas Transportation Institute rain range. In these studies, the AWP and conventional markings demonstrated substantial differences in retroreflectivity; however, these studies were not conducted under real-world driving conditions, and they could not address any issues with contractors applying the markings in a dynamic environment where application time must be considered to keep traffic moving.

To build on the findings of Phase I, the Phase II effort aims to study actual drivers as they navigate through work zones by comparing standard pavement marking to the AWP under daytime, nighttime, and rainy conditions. First, the research team conducted a literature review to learn from previous research in the area of pavement marking studies. Following this effort, they selected field test sites based on a variety of factors, including a minimum of two lanes per direction in the transition zone, no raised pavement markers (RPMs), a minimum speed limit of 45 miles per hour, and no disruption from nearby traffic signals. In total, five sites were chosen, three in North Carolina and two in Ohio. Next, standard pavement marking and the AWP were applied in each of the chosen work zones. The analysis considered four measures of effectiveness (MOE): retroreflectivity, speeds, lane encroachments, and lateral lane placement. Retroreflectivity was utilized to determine differences in pavement marking application across sites and between pavement marking types at the same site. Speed was used to supplement findings from the latter two MOEs since higher or lower speeds could not be correlated to better or worse driving conditions. Last, lane encroachment and lateral lane placement were the primary MOEs used to determine if safety had improved using the new AWP.

Page last modified on July 5, 2016
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