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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 on the performance of drivers during nighttime driving in rain using visual headlamp technologies and visual headlamp technologies augmented with in-vehicle displays for near- and far-infrared sensors. 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 XIV. 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-04-145

2. Government Accession No.

3. Recipient’s Catalog No.

4. Title and Subtitle
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

5. Report Date
December 2005

6. Performing Organization Code

7. Author(s)
Vicki H. Williams, Ronald B. Gibbons, 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
Enhanced Night Visibility Series Phase III, Study 2 (rainy weather) was performed following the same procedures used for Phase III, Study 1 (clear weather). Study 2 served to expand the knowledge of how current vision enhancement systems can affect detection and recognition of different types of objects while driving during adverse weather, specifically during rainy conditions. The empirical testing for this study was performed on the Virginia Smart Road; the rain was controlled by weather-making equipment. Fifteen participants were involved in the study. A 4 by 8 by 3 mixed factorial design was used to investigate the effects of different types of vision enhancement systems, different types of objects on the roadway, and driver’s age on detection and recognition distances; subjective evaluations also were obtained for the different vision enhancement systems.

The results of the empirical testing suggest that well-designed infrared (IR) systems are consistently associated with often significantly longer detection distances for most types of pedestrian objects during rainy conditions. In particular, the use of the near IR (NIR) systems resulted in earlier detection of nearly all tested pedestrian types than did the use of either far IR (FIR) or baseline halogen (HLB) systems. The exception to this finding is the case in which the pedestrian is on the right side of a right (1,250-m (4,101-ft) radius) curve. In this case, the NIR system was associated with similar or shorter (though not significantly so) detection distances than the FIR and HLB systems. Drivers in this study detected the nonpedestrian object (tire tread) at similar distances regardless of the headlamp system in use (NIR, FIR, or HLB). This indicates that there is no significant loss in detection distance for small, low-contrast objects (such as tire treads) among the types of headlamps tested in this study. All of these findings appear to be applicable regardless of driver age. Subjective comments by the drivers in this study tend to be consistent with the objective results discussed above.

17. Key Words
Detection, Recognition, Night Vision, Visibility Vision Enhancement System, Infrared, Headlamp, Pedestrian, Halogen, Rain

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
82

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 14th 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—CONCLUSIONS

APPENDIX A—SCREENING QUESTIONNAIRE
APPENDIX B—INFORMED CONSENT FORM
APPENDIX C—VISION TEST
APPENDIX D—ANOVA TABLES FOR PEDESTRIANS IN STRAIGHT SECTIONS
APPENDIX E—ANOVA TABLES FOR PEDESTRIANS IN CURVES (TURNS)
APPENDIX F—ANOVA TABLES FOR POST-DRIVE QUESTIONNAIRE

REFERENCES


LIST OF FIGURES

  1. Photo. Headlamp testing rack.
  2. Photo. Object: pedestrian, blue denim clothing, left (BlueLF).
  3. Photo. Object: pedestrian, blue denim clothing, right (BlueRT).
  4. Photo. Object: pedestrian in left turn, left side (LFtrnLF).
  5. Photo. Object: pedestrian in left turn, right side (LFtrnRT).
  6. Photo. Object: pedestrian in right turn, left side (RTtrnLF).
  7. Photo. Object: pedestrian in right turn, right side (RTtrnRT).
  8. Photo. Object: dynamic pedestrian (PedDyno).
  9. Photo. Object: tire tread.
  10. Diagram. Likert-type subjective rating scale.
  11. Photo. Data collection display screen.
  12. Photo. Smart Road.
  13. Diagram. Roadway layout.
  14. Bar graph. Tire detection and recognition distances.
  15. Bar graph. Blue-clothed pedestrian on straight: left and right side detection and recognition distances.
  16. Bar graph. Dynamic pedestrian on straight: detection and recognition distances.
  17. Bar graph. Blue-clothed pedestrian in left turn: left and right side detection and recognition distances.
  18. Bar graph. Blue-clothed pedestrian in right turn: left and right side detection and recognition distances.
  19. Bar graph. Mean subjective ratings by VES for statement 1: "This vision enhancement system allowed me to detect objects sooner than my regular headlights."
  20. Bar graph. Mean subjective ratings by VES for statement 2: "This vision enhancement system allowed me to identify objects sooner than my regular headlights."
  21. Bar graph. Mean subjective ratings by VES for statement 5: "This vision enhancement system did not cause me any more visual discomfort than my regular headlights."
  22. Equation. Braking distance approximation.
  23. Diagram. Graphics for detection distances.
  24. Diagram. FIR mean detection distances.
  25. Diagram. NIR 1 mean detection distances.
  26. Diagram. NIR 2 mean detection distances.
  27. Diagram. HLB mean detection distances.

LIST OF TABLES

  1. VES orders for participants. Each participant was assigned an order (1, 2, 3, or 4) that indicates the VES used for each lap.
  2. The eight objects used in this study.
  3. VES configurations.
  4. Object descriptions and illustrations.
  5. Tire tread ANOVA summary table for the dependent measurement: detection distance.
  6. Tire tread ANOVA summary table for the dependent measurement: recognition distance.
  7. Summary of significant main effects and interactions for the Likert-type scales.
  8. Stopping distances needed for a wet roadway.
  9. Detection distances by types of object and potential detection inadequacy when compared to stopping distance at various speeds: FIR.
  10. Detection distances by types of object and potential detection inadequacy when compared to stopping distance at various speeds: NIR 1.
  11. Detection distances by types of object and potential detection inadequacy when compared to stopping distance at various speeds: NIR 2.
  12. Detection distances by types of object and potential detection inadequacy when compared to stopping distance at various speeds: HLB.
  13. Percentage differences from FIR: detection distances by VES and object.
  14. Percentage differences from FIR: recognition distances by VES and object.
  15. Percentage differences from NIR 1: detection distances by VES and object.
  16. Percentage differences from NIR 1: recognition distances by VES and object.
  17. Percentage differences from NIR 2: detection distances by VES and object.
  18. Percentage differences from NIR 2: recognition distances by VES and object.
  19. Percentage differences from HLB: detection distances by VES and object.
  20. Percentage differences from HLB: recognition distances by VES and object.
  21. Detection in rain compared to clear for a pedestrian on the left in a left turn.
  22. Detection in rain compared to clear for a pedestrian on the left in a right turn.
  23. Detection in rain compared to clear for a pedestrian on the right in a left turn.
  24. Detection in rain compared to clear for a pedestrian on the right in a right turn.
  25. Detection in rain compared to clear for a pedestrian on the left.
  26. Detection in rain compared to clear for a pedestrian on the right.
  27. Detection in rain compared to clear for a tire tread.
  28. Pedestrian, denim clothing, left ANOVA summary table for the dependent measurement: detection distance.
  29. Pedestrian, denim clothing, left ANOVA summary table for the dependent measurement: recognition distance.
  30. Pedestrian, denim clothing, right ANOVA summary table for the dependent measurement: detection distance.
  31. Pedestrian, denim clothing, right ANOVA summary table for the dependent measurement: recognition distance.
  32. Dynamic pedestrian ANOVA summary table for the dependent measurement: detection distance.
  33. Dynamic pedestrian ANOVA summary table for the dependent measurement: recognition distance.
  34. Pedestrian in left turn, left side ANOVA summary table for the dependent measurement: detection distance.
  35. Pedestrian in left turn, left side ANOVA summary table for the dependent measurement: recognition distance.
  36. Pedestrian in left turn, right side ANOVA summary table for the dependent measurement: detection distance.
  37. Pedestrian in left turn, right side ANOVA summary table for the dependent measurement: recognition distance.
  38. Pedestrian in right turn, left side ANOVA summary table for the dependent measurement: detection distance.
  39. Pedestrian in right turn, left side ANOVA summary table for the dependent measurement: recognition distance.
  40. Pedestrian in right turn, right side ANOVA summary table for the dependent measurement: detection distance.
  41. Pedestrian in right turn, right side ANOVA summary table for the dependent measurement: recognition distance.
  42. ANOVA summary table for the Likert-type scale on detection.
  43. ANOVA summary table for the Likert-type scale on recognition.
  44. ANOVA summary table for the Likert-type scale on lane-keeping assistance.
  45. ANOVA summary table for the Likert-type scale on roadway direction.
  46. ANOVA summary table for the Likert-type scale on visual discomfort.
  47. ANOVA summary table for the Likert-type scale on overall safety rating.
  48. ANOVA summary table for the Likert-type scale on overall VES evaluation.

LIST OF ACRONYMS AND ABBREVIATIONS

 

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