U.S. Department of Transportation
Federal Highway Administration
Research, Development, and Technology
Turner-Fairbank Highway Research Center
6300 Georgetown Pike
McLean, VA 22101-2296
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 rain. 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 IV. 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.
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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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1. Report No. FHWA-HRT-04-135 |
2. Government Accession No. |
3. Recipient’s Catalog No. |
4. Title and Subtitle Enhanced Night Visibility Series, Volume IV:
Phase II—Study 2: Visual Performance During Nighttime Driving in Rain
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5. Report Date December 2005 |
6. Performing Organization Code
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7. Author(s)
Myra Blanco, Jonathan M. Hankey, Thomas A. Dingus |
8. Performing Organization Report No.
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9. Performing Organization Name and Address
Virginia Tech Transportation Institute
3500 Transportation Research Plaza
Blacksburg, VA 24061 |
10. Work Unit No. (TRAIS)
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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
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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
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16. Abstract
Phase II, Study 2 (rainy weather) was performed following the same procedures used for Study 1 (clear weather). Study 2 helped 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 rain conditions. The empirical testing for this study was performed on the Virginia Smart Road; the rain was controlled by weathermaking equipment. Thirty participants were involved in the study. A 12 by 7 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 vision enhancement systems that include halogen headlamps as their main component (i.e., halogen alone or halogen with ultraviolet A) consistently allow drivers the best detections during rain conditions. In fact, the halogen headlamp (low-beam configuration) provides the longest detection and recognition distances overall; in the few trials where other systems allow farther detection distances, these differences did not represent meaningful improvements. Even drivers using the infrared thermal imaging system, which resulted in farther detection distances for pedestrians and cyclists under clear conditions, perform no differently in the rain than when only the low beams of the vehicle were used.
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17. Key Words
Age, Cyclist, Detection, Halogen, Headlamp, High Intensity Discharge (HID), Infrared, Night Vision, Nighttime, Pedestrian, Rain, Recognition, Vision Enhancement System, Weather
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18. Distribution Statement
No restrictions. This document is available through the National Technical Information Service; Springfield, Virginia 22161.
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19. Security Classif. (of this report)
Unclassified
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20. Security Classif. (of this page)
Unclassified
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21. No. of Pages 141 |
22. Price |
This volume is the fourth 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,” etc. 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 |