EFFECTIVENESS OF REFLECTORIZED HEADLAMPS
ONE HAZARD ASSOCIATED WITH NIGHT DRIVING IS THE PROBLEM OF ENCOUNTERING VEHICLES WITH ONLY ONE LIGHTED HEADLAMP. RECENT INVESTIGATION INTO THE ONE-EYED VEHICLE PROBLEM LED TO THE PROPOSED USE OF REFLEX-REFLECTIVE MATERIALS INCLUDED WITHIN A HEADLAMP TO ACT AS A SAFETY DEVICE. SHOULD HEADLAMP FAILURE OCCUR, REFLECTED LIGHT WOULD PERMIT EARLY DISCRIMINATION OF THE UNLIT LAMP POSITION, THUS AFFORDING POSITIVE VEHICLE DELINEATION. A HEADLAMP OF THIS TYPE WAS DEVELOPED WHICH PROVIDES 6.9 CANDLEPOWER PER INCIDENT FOOTCANDLE PER UNIT AT 0.2 DEGREES DIVERGENCE AND 0 DEGREES INCIDENCE, SOMEWHAT HIGHER THAN THE MINIMUM VALUE OF 4.5 CANDLEPOWER PER FOOT-CANDLE VALUE SPECIFIED FOR CLASS A RED REFLEX-REFLECTORS BY THE SOCIETY OF AUTOMOTIVE ENGINEERS FOR IDENTICAL CONDITIONS. FINDINGS ARE REPORTED OF A RESEARCH STUDY DESIGNED TO EVALUATE THE EFFECTIVENESS OF THE REFLECTORIZED HEADLAMP UNDER REALISTIC NIGHT DRIVING CONDITIONS. THE ESTABLISHED PARAMETER WAS THE DISTANCE AT WHICH THE UNLIT SIDE OF AN APPROACHING ONE-EYED CAR COULD BE DETECTED FOR VEHICLES EQUIPPED WITH CONVENTIONAL HEADLAMPS AND FOR VEHICLES EQUIPPED WITH REFLECTORIZED HEADLAMPS. VARIABLES CONSIDERED WERE DRY AND SIMULATED RAIN CONDITIONS, THREE RATES OF CLOSURE, AND BOTH SIDES OF THE VEHICLE. MEAN DETECTION DISTANCES ESTABLISHED WERE 472 FT AND 288 FT FOR THE REFLECTORIZED AND CONVENTIONAL HEADLAMP CONDITIONS RESPECTIVELY. COMPARISON OF DETECTION DISTANCES OBTAINED FOR REFLECTORIZED HEADLAMPS TO MOTORIST PERCEPTION-REACTION DISTANCE ESTABLISHED A SIGNIFICANT IMPROVEMENT IN TIME AVAILABLE FOR EVASIVE ACTION.
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Supplemental Notes:
- Paper sponsored by Committee on Night Visibility and presented at the 45th Annual Meeting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Hanson, Douglas R
- Palmquist, Philip V
- Publication Date: 1967
Media Info
- Media Type: Digital/other
- Features: Figures; References; Tables;
- Pagination: pp 8-16
- Monograph Title: Night visibility
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Serial:
- Highway Research Record
- Issue Number: 164
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Alternatives analysis; Drivers; Driving; Dryness; Failure; Hazards; Headlamps; Night; Rainfall; Reaction time; Reduction (Chemistry); Reflectorized materials
- Uncontrolled Terms: Driver reaction; Dry conditions
- Old TRIS Terms: Reaction distance; Reduction; Reflectorization
- Subject Areas: Highways; Safety and Human Factors;
Filing Info
- Accession Number: 00219905
- Record Type: Publication
- Report/Paper Numbers: HS-000 708
- Files: TRIS, TRB
- Created Date: Apr 20 1994 12:00AM