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Publication Number: FHWA-HRT-04-136
Date: December 2005

Enhanced Night Visibility, Volume V: Phase II—Study 3: Visual Performance During Nighttime Driving in Snow

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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 visual performance of drivers during nighttime driving in snow. The study was conducted under Phase II of the Enhanced Night Visibility (ENV) project, a comprehensive evaluation of evolving and proposed headlamp technologies under 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 V. 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-04-136

2. Government Accession No.

3. Recipient's Catalog No.

4. Title and Subtitle
Enhanced Night Visibility Series, Volume V:
Phase II–Study 3 Visual Performance During Nighttime Driving in Snow

5. Report Date
December 2005

6. Performing Organization Code

7. Author(s)
M. Lucas Neurauter, Myra Blanco, 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
Phase II, Study 3 was part of the Enhanced Night Visibility project, a larger research effort investigating drivers' visual performance during nighttime driving. Study 3 helped expand the knowledge of how current vision enhancement systems can affect detection and recognition of different types of objects during adverse weather, specifically for snow conditions. A total of 20 participants detected and recognized different roadway objects while driving experimental vehicles equipped with various headlamps in a snow condition. A 4 by 3 by 2 mixed factorial design was used to investigate the effects of the different types of vision enhancement systems, the types of objects on the roadway, and driver's age on detection and recognition distances. Subjective evaluations for the different systems were obtained as well.

The results of the empirical testing suggest that halogen low beam (HLB) configurations combined with an ultraviolet A (UV–A) setup consistently outperform the HLB by itself and the high intensity discharge (HID) configuration with respect to detecting and recognizing pedestrians in a snow environment. All three HLB configurations significantly outperformed the HID configuration for both detection and recognition of the objects presented. The three HLB configurations were not significantly different from each other with respect to recognition distances; however, there was a slight but significant increase in detection distance when the HLB was paired with one of the UV–A systems used. Finally, there were no significant findings for the subjective analysis, although there were some conflicting findings between the subjective and objective data.

17. Key Words
Age, Detection, Halogen, Headlamp, High Intensity Discharge (HID), Infrared, Pedestrian, Night Vision, Nighttime, Recognition, Snow, Ultraviolet, Vision Enhancement System, Weather

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
103

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 fifth 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 AND CONCLUSIONS

REFERENCES

LIST OF FIGURES

  1. Photo. Perpendicular pedestrian in white clothing.
  2. Photo. Parallel pedestrian in white clothing.
  3. Photo. Perpendicular pedestrian in black clothing.
  4. Photo. Five UV–A + halogen low beam.
  5. Photo. Hybrid UV–A + halogen low beam.
  6. Photo. High intensity discharge.
  7. Photo. Snowmaking on the Virginia Smart Road.
  8. Diagram. Locations where the objects were presented for the adverse weather condition (note the area where snow was generated).
  9. Bar graph. Bonferroni post hoc results on detection and recognition distances for the main effect: VES.
  10. Bar graph. Bonferroni post hoc results on detection and recognition distances for the main effect: object.
  11. Equation. Braking distance.
  12. Equation. Total stopping distance for brake reaction time plus braking distance.
  13. Equation. AASHTO calculation of coefficient of friction for wet pavement.
  14. Bar graph. Participants' visual acuity divided by age group.
  15. Bar graph. Participants' contrast sensitivity at 1.5 cycles per degree (cpd) divided by age group.
  16. Bar graph. Participants' contrast sensitivity at 3.0 cpd divided by age group.
  17. Bar graph. Participants' contrast sensitivity at 6.0 cpd divided by age group.
  18. Bar graph. Participants' contrast sensitivity at 12.0 cpd divided by age group.
  19. Bar graph. Participants' contrast sensitivity at 18.0 cpd divided by age group.
  20. Photo. Aerial view of the Virginia Smart Road.

LIST OF TABLES

  1. Experimental design: 4 by 3 by 2 mixed-factor design (four VES configurations, two age groups, three objects).
  2. The three objects presented in each cell of table 1.
  3. Example of the VES configuration order for a pair of participants.
  4. Description of the objects.
  5. Model for the experimental design.
  6. ANOVA summary table for the dependent measurement: detection distance.
  7. ANOVA summary table for the dependent measurement: recognition distance.
  8. Summary of significant main effects and interactions.
  9. ANOVA summary table for the Likert-type rating for detection.
  10. ANOVA summary table for the Likert-type rating for recognition.
  11. ANOVA summary table for the Likert-type rating for lane-keeping assistance.
  12. ANOVA summary table for the Likert-type rating for roadway direction.
  13. ANOVA summary table for the Likert-type rating for visual discomfort.
  14. ANOVA summary table for the Likert-type rating for overall safety rating.
  15. ANOVA summary table for the Likert-type rating for overall VES evaluation.
  16. Mean detection and recognition distances (units: feet) during nighttime driving.
  17. Differences in detection distances (units: feet) between clear, rain, and snow environments.
  18. Difference in reaction time (units: seconds) available depending on vehicle speed, based on the difference of detection time from HLB.
  19. Stopping distances needed for wet roadways due to snow.
  20. Detection distances by type of object and potential detection inadequacy when compared to stopping distance at various speeds: five UV–A + HLB.
  21. Detection distances by type of object and potential detection inadequacy when compared to stopping distance at various speeds: hybrid UV–A + HLB.
  22. Detection distances by type of object and potential detection inadequacy when compared to stopping distance at various speeds: HLB.
  23. Detection distances by type of object and potential detection inadequacy when compared to stopping distance at various speeds: HID.
  24. Comparison of distance between detection and recognition.

LIST OF ACRONYMS AND ABBREVIATIONS

 

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