TFHRC Home > Safety > Safety Publications > Updates to Research on Recommended Minimum Levels for Pavement Marking Retroreflectivity to Meet Driver Night Visibility Needs
October 2007
FHWA-HRT-07-059
U.S. Department of Transportation
Federal Highway Administration
Research, Development, and Technology
Turner-Fairbank Highway Research Center
6300 Georgetown Pike
McLean, VA 22101-2296
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In 1992, the Congress directed the Secretary of Transportation to revise the Manual on Uniform Traffic Control Devices to include a standard for minimum levels of retroreflectivity that must be maintained for pavement markings. While previous research has been undertaken to recommend minimum pavement marking retroreflectivity levels, the need existed to update the earlier research in light of changes in roadway user characteristics, vehicle preferences, headlamp performance, and available research tools. Based on a newer, more powerful analytical tool, the following document provides updated recommended minimum levels for pavement marking retroreflectivity to meet driver night visibility needs.
This report will be of interest to State and local agencies with responsibility for pavement marking and people involved in pavement marking maintenance.
Michael F. Trentacoste
Director, Office of SafetyResearch and Development
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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16. Abstract In this study, the Pavement Marking Visibility Module of the Tarvip model was validated by comparing field data from various studies to prediction results under similar conditions from Tarvip. Next, a comprehensive survey on the factors that affect pavement marking visibility and minimum R L levels was performed, with key factors identified, including pavement marking configuration, pavement surface type, vehicle speed, vehicle type, and presence of RRPMs. From these key factors, a methodology of using Tarvip to do a sensitivity analysis on factors modeled in it was developed. The plan was executed, and resulting R L values under typical conditions on United States roadways formed the basis of new recommendations. Finally, limitations of the recommendations were analyzed, and a plan for future research was presented. |
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Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
SI* (Modern Metric) Conversion Factors
INTRODUCTION
1.1. Problem Statement
1.2. Research Objectives
LITERATURE REVIEW
2.1. Minimum Pavement Marking Retroreflectivity Proposals
2.2. Minimum Pavement Marking Retroreflectivity Research
2.3. Key Factors Affecting Pavement Marking Visibility
2.3.1. Pavement Marking Retroreflectivity
2.3.2. Pavement Surface Material
2.3.3. Vehicle Type
2.3.4. Vehicle Headlamps
2.3.5. Overhead Lighting
2.3.6. Edge Line Presence
2.3.7. Wider Longitudinal Markings
2.3.8. RRPM Presence
2.3.9. Driver Age
2.3.10. Preview Time
2.3.11. Summary of Key Factors
RESEARCH METHODOLOGY
3.1. Description of Tarvip
3.2. Using the TARVIP Model
3.3. Validation of the TARVIP Model
3.3.1. TTI Report 5008-1 Study Comparison
3.3.2. TTI Report 4269-1 Study Comparison
ESTABLISHING CRITERIA FOR MINIMUM PAVEMENT MARKING RETROREFLECTIVITY
4.1. Selection of Pavement Surfaces
4.2. Selection of Pavement marking Configurations
4.3. Selection of Vehicle Types
4.4. Selection of Operating Speeds
4.5. Consideration of Roadway Lighting
4.6. Selection of Pavement marking Materials
4.7. Selection of Vehicle Headlamp Performance
4.8. Establishment of Required Preview Time
4.9. Selection of Driver Age and Visual Performance
4.10. Consideration of RRPMs
4.11. Determining Minimum Pavement marking Retroreflectivity
Figure 1. Bar graph. Detection distance versus pavement marking retroreflectivity.
Figure 2. Bar graph. Saturated condition visibility distance versus marking type and vehicle type.
Figure 3. Bar graph. Average skip line detection distance versus vehicle type.
Figure 4. Screen shot. Plot of iso-lux curves on road surface (TARVIP screen shot).
Figure 5. Scatter diagram. Detection distance versus driver age—Structured tape.
Figure 6. Scatter diagram. Detection distance versus driver age—Thermoplastic.
Figure 7. Scatter diagram. Detection distance versus driver age—Standard tape.
Figure 8. Bar graph/line graph. Maximum speed limits in U.S. states and associated VMT.
Table 1. FWHA research recommendations for minimum pavement marking retroreflectivity.
Table 2. Zwahlen’s recommended minimum RL values.
Table 3. Workshop-proposed speed-based minimum pavement marking retroreflectivity values.
Table 4. Workshop-proposed classification-based minimum pavement marking retroreflectivity values.
Table 5. ATSSA recommended minimum RL values.
Table 6. Headlamp illuminance along edge lines and center lines.
Table 7. Summary of key factors affecting pavement marking visibility.
Table 8. Other factors affecting pavement marking visibility.
Table 9. Minimum retroreflectivity levels in [mcd/m^2/lx].
Table 10. Required RL values for TARVIP scenarios with varying preview time in [mcd/m^2/lx].
Table 11. Recommended minimum RL values in [mcd/m2/lux].
FHWA-HRT-07-059
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