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Publication Number: FHWA-HRT-04-145
Date: December 2005

Enhanced Night Visibility Series, Volume XIV: Phase III—Study 2: Comparison of Near Infrared, Far Infrared, and Halogen Headlamps on Object Detection in Nighttime Rain

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U.S. Department of Transportation

Federal Highway Administration

Research, Development, and Technology

Turner–Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101–2296


FOREWORD

The overall goal of the Federal Highway Administration’s (FHWA) Visibility Research Program is to enhance the safety of road users through near-term improvements of the visibility on and along the roadway. The program also promotes the advancement of new practices and technologies to improve visibility on a cost-effective basis.

The following document summarizes the results of a study evaluating the influence of headlamp beam characteristics on discomfort and disability glare from various headlamp systems. The study was conducted under Phase III of the Enhanced Night Visibility (ENV) project, a comprehensive evaluation of evolving and proposed headlamp technologies in various weather conditions. The individual studies within the overall project are documented in an 18-volume series of FHWA reports, of which this is Volume XV. It is anticipated that the reader will select those volumes that provide information of specific interest.

This report will be of interest to headlamp designers, automobile manufacturers and consumers, third-party headlamp manufacturers, human factors engineers, and people involved in headlamp and roadway specifications.

 

Michael F. Trentacoste
Director, Office of Safety
    Research and Development

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.

Technical Report Documentation Page

1. Report No.
FHWA-HRT-04-146

2. Government Accession No.

3. Recipient’s Catalog No.

4. Title and Subtitle
Enhanced Night Visibility Series, Volume XV: Phase III—Study 3: Influence of Beam Characteristics on Discomfort and Disability Glare

5. Report Date
December 2005

6. Performing Organization Code

7. Author(s)
Jason Clark, Ronald B. Gibbons, and Jonathan M. Hankey

8. Performing Organization Report No.

9. Performing Organization Name and Address
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061

10. Work Unit No.

11. Contract or Grant No.
DTFH61-98-C-00049

12. Sponsoring Agency Name and Address
Office of Safety Research and Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296

13.Type of Report and Period Covered
Final Report

14. Sponsoring Agency Code
HRDS-05

15. Supplementary Notes
Contracting Officer’s Technical Representative (COTR): Carl Andersen, HRDS-05

16. Abstract
The objective of this study was to evaluate the discomfort and disability glare produced by oncoming headlamps with varying beam intensity and distribution. Oncoming headlamps can be visually discomforting and disabling to drivers at night. In recent years, high intensity discharge (HID) headlamps have raised some concern because of their increased light output and brighter appearance than traditional halogen headlamps.

During the discomfort glare portion of this study, participants drove an experimental vehicle at 32 km/h (20 mi/h) past stationary glare headlamps. They were asked to rate their overall discomfort using the subjective deBoer scale. The disability glare portion involved drivers detecting a static pedestrian either near the road centerline or near the road edgeline while approaching different sets of glare headlamps. It was hypothesized that there would be significant differences in detection distance, illuminance at the driver’s eye, and discomfort glare rating across the different glare headlamp, pedestrian position, adaptation level, and participant age combinations.

The main effect of glare headlamp was the only significant factor in the analysis for discomfort glare. The main effects of age, glare headlamp, and pedestrian location were all significant in the analysis for the disability glare portion. In addition, the interaction of pedestrian location and glare headlamp was significant. Overall, headlamps that had higher subjective discomfort ratings were the same lamps that had worse objective disability measures.

The conclusions of this research will be valuable to the consumer as well as the manufacturers and designers of future headlamps in revealing how glare can affect drivers on the road at night. This information can help guide new designs to maximize forward visibility while minimizing glare.

17. Key Words
deBoer, Detection, Disability Glare, Discomfort Glare, Halogen, High Intensity Discharge, Illuminance, Pedestrian

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

19. Security Classif. (of this report)
Unclassified

20. Security Classif. (of this page)
Unclassified

21. No. of Pages
119

22. Price

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


SI* (Modern Metric) Conversion Factors


ENHANCED NIGHT VISIBILITY PROJECT REPORT SERIES

This volume is the 15th of 18 volumes in this research report series. Each volume is a different study or summary, and any reference to a report volume in this series will be referenced in the text as “ENV Volume I,” “ENV Volume II,” and so forth. A list of the report volumes follows:

Volume Title Report Number
  I           Enhanced Night Visibility Series: Executive Summary FHWA-HRT-04-132
  II           Enhanced Night Visibility Series: Overview of Phase I and
Development of Phase II Experimental Plan
FHWA-HRT-04-133
  III           Enhanced Night Visibility Series: Phase II—Study 1: Visual
Performance During Nighttime Driving in Clear Weather
FHWA-HRT-04-134
  IV           Enhanced Night Visibility Series: Phase II—Study 2: Visual
Performance During Nighttime Driving in Rain
FHWA-HRT-04-135
  V           Enhanced Night Visibility Series: Phase II—Study 3: Visual
Performance During Nighttime Driving in Snow
FHWA-HRT-04-136
  VI           Enhanced Night Visibility Series: Phase II—Study 4: Visual
Performance During Nighttime Driving in Fog
FHWA-HRT-04-137
  VII           Enhanced Night Visibility Series: Phase II—Study 5: Evaluation of
Discomfort Glare During Nighttime Driving in Clear Weather
FHWA-HRT-04-138
  VIII           Enhanced Night Visibility Series: Phase II—Study 6: Detection of
Pavement Markings During Nighttime Driving in Clear Weather
FHWA-HRT-04-139
  IX           Enhanced Night Visibility Series: Phase II—Characterization of
Experimental Objects
FHWA-HRT-04-140
  X           Enhanced Night Visibility Series: Phase II—Visual Performance
Simulation Software for Objects and Traffic Control Devices
FHWA-HRT-04-141
  XI           Enhanced Night Visibility Series: Phase II—Cost-Benefit Analysis FHWA-HRT-04-142
  XII           Enhanced Night Visibility Series: Overview of Phase II and
Development of Phase III Experimental Plan
FHWA-HRT-04-143
  XIII           Enhanced Night Visibility Series: Phase III—Study 1: Comparison
of Near Infrared, Far Infrared, High Intensity Discharge, and Halogen Headlamps on Object Detection in Nighttime Clear Weather
FHWA-HRT-04-144
  XIV           Enhanced Night Visibility Series: Phase III—Study 2: Comparison
of Near Infrared, Far Infrared, and Halogen Headlamps on Object Detection in Nighttime Rain
FHWA-HRT-04-145
  XV           Enhanced Night Visibility Series: Phase III—Study 3: Influence of
Beam Characteristics on Discomfort and Disability Glare
FHWA-HRT-04-146
  XVI           Enhanced Night Visibility Series: Phase III—Characterization of
Experimental Objects
FHWA-HRT-04-147
  XVII           Enhanced Night Visibility Series: Phases II and III—
Characterization of Experimental Vision Enhancement Systems
FHWA-HRT-04-148
  XVIII           Enhanced Night Visibility Series: Overview of Phase III FHWA-HRT-04-149

TABLE OF CONTENTS

CHAPTER 1—INTRODUCTION

CHAPTER 2—METHODS

CHAPTER 3—RESULTS CHAPTER 4—DISCUSSION

CHAPTER 5—SUMMARY

APPENDIX A—SCREENING QUESTIONNAIRE

APPENDIX B—INFORMED CONSENT FORM

APPENDIX C—VISION TEST FORM

APPENDIX D—IN-VEHICLE EXPERIMENTAL PROTOCOL

APPENDIX E—ONROAD EXPERIMENTAL PROTOCOL

APPENDIX F—AIMING PROTOCOL

APPENDIX G—VES CHARACTERISTICS

APPENDIX H—PREDRIVE QUESTIONNAIRE

APPENDIX I—RESULTS ANOVA TABLES

APPENDIX J—RESULTS FOR ANOVA WITHOUT THE LOW/WIDE VES

REFERENCES

LIST OF FIGURES

  1. Line graph. Spectral power distribution of typical HID and halogen headlamps.
  2. Line graph. Illuminance readings taken on a divided highway at night with and without overhead lighting and glare.
  3. Photo. Light source used to control driver light adaptation level.
  4. Photo. Brightness Acuity Tester.
  5. Photo. Back view of glare cart with halogen VESs (low/narrow) mounted.
  6. Photo. Glare cart and experimental vehicle on the Smart Road.
  7. Photo. Glare cart with VESs at night with left pedestrian.
  8. Diagram. Plan view of the participant vehicle at the start point in the discomfort glare portion.
  9. Diagram. Plan view of the participant vehicle at the start point for the disability glare portion with right pedestrian.
  10. Bar graph. deBoer discomfort ratings for the main effect of VES (scale of 1 to 9).
  11. Bar graph. Mean detection distances for the interaction of pedestrian and VES.
  12. Bar graph. Mean detection distances for the main effect of VES with SNK groupings.
  13. Bar graph. Mean detection distances for the main effect of age group with SNK groupings.
  14. Bar graph. Mean illuminance readings (lx) at moment of detection for the Pedestrian by VES by Age interaction.
  15. Bar graph. Mean illuminance readings (lx) at moment of detection for the VES by Age interaction.
  16. Bar graph. Mean illuminance readings (lx) at moment of detection for the Pedestrian by Age interaction.
  17. Bar graph. Mean illuminance readings (lx) at moment of detection for the Pedestrian by VES interaction.
  18. Bar graph. Mean illuminance readings (lx) at moment of detection for the main effect of VES with SNK groupings.
  19. Bar graph. Mean illuminance readings (lx) at moment of detection for the main effect of age group with SNK grouping.
  20. Bar graph. BAT results by age group.
  21. Line graph. The relationship between headlamp intensity and perceived glare.
  22. Photo. Front view of HID 1 headlamp (high/narrow).
  23. Photo. Front view of HID 2 headlamp (high/wide).
  24. Photo. Front view of HID 3 headlamp (medium/medium).
  25. Photo. Front view of HID 4 headlamp (low/wide).
  26. Photo. Front view of halogen headlamp (low/narrow).
  27. Bar graph. Secondary analysis mean detection distances for the interaction of pedestrian and VES.
  28. Bar graph. Mean illuminance readings (lx) at moment of detection for the Pedestrian by VES interaction without the low/wide VES.

LIST OF TABLES

  1. Factors for the experimental design: 5 (VESs) by 3 (age) mixed factor design.
  2. Two pedestrian locations and two adaptation levels corresponding to each cell in table 1.
  3. Available VESs categorized by width (degrees) and intensity (candela).
  4. VES characteristic matrix.
  5. Object descriptions.
  6. Typical results of normal glare sensitivity with BAT.
  7. Typical results of mild glare sensitivity with BAT.
  8. Typical results of severe glare sensitivity with BAT.
  9. Mixed-factor design for discomfort glare.
  10. Mixed-factor design for detection distance and illuminance.
  11. Significant main effects and interactions.
  12. Discomfort glare SNK groupings for the VES main effect.
  13. Detection distance SNK groupings for the VES main effect.
  14. Illuminance SNK groupings for the VES main effect.
  15. ANOVA table for discomfort glare results.
  16. ANOVA table for the objective measurement of disability glare with detection distances.
  17. ANOVA table for the objective measurement of driver’s eye illuminance.
  18. Secondary analysis ANOVA significant main effects and interactions.
  19. Secondary analysis ANOVA table for discomfort glare rating.
  20. Discomfort glare SNK groupings comparison for the VES main effect.
  21. Secondary analysis ANOVA table for detection distances.
  22. Detection distance SNK groupings comparison for the VES main effect.
  23. Detection distance SNK groupings comparison for the age main effect.
  24. Secondary analysis ANOVA table for the objective measurement of driver’s eye illuminance.
  25. Illuminance SNK groupings comparison for the VES main effect.
  26. Illuminance SNK groupings comparison for the age main effect.


LIST OF ACRONYMS AND ABBREVIATIONS

 

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