SPECIFICATIONS AND PERFORMANCE OF NEW SEALED-BEAM HEADLAMP
RESULTS ARE REPORTED OF AN ENGINEERING AND DEVELOPMENT PROGRAM AIMED AT IMPROVING THE SEALED-BEAM HEADLAMP FOR AUTOMOBILES. BECAUSE OF HEAVY HIGHWAY TRAFFIC, NIGHT-DRIVING CONDITIONS CREATE A NEED OF DRIVING WITH THE LOWER BEAM. THIS RESULTS IN THE NEED FOR AN IMPROVEMENT IN THE LOWER BEAM PATTERN WHICH WOULD SATISFY HEADLIGHT REQUIREMENTS THROUGH A WIDER RANGE OF DRIVING SITUATIONS. A CONSIDERABLE INCREASE IN LIGHT INTENSITY DIRECTED AT THE RIGHT HAND SIDE OF THE VEHICLE PATH WAS NEEDED DURING THE TIMES THE VEHICLE IS OPERATED WITH THE LAMPS ON THE LOWER BEAMS. ELEVEN DIFFERENT LAMP DESIGNS, REPRESENTING A PLANNED EFFORT AT MODIFYING LAMP CHARACTERISTICS, WERE DEVELOPED AND SUBMITTED BY THE VARIOUS LAMP MANUFACTURERS. A FILAMENT CAP WAS DEVELOPED FOR MOUNTING ABOVE THE LOWER BEAM FILAMENT TO REDUCE THE STRAY LIGHT PROJECTED UPWARD FROM THE FILAMENT. THIS PRODUCED BENEFITS FOR THE DRIVER IN ADVERSE WEATHER SITUATIONS. AN INCREASE IN LIGHT AT THE SOURCE WAS ACCOMPLISHED BY RAISING THE WATTAGE OF EACH FILAMENT BY FIVE WATTS. PART OF THE MODIFICATION OF THE LAMP SPECIFICATION IS ACCOMPLISHED BY A CHANGE IN THE AIM SPECIFICATION SO THE GEOMETRIC CENTER OF THE ZONE OF HIGHEST INTENSITY OF THE UPPER BEAM FALLS 0.4 DEGREE BELOW THE PHOTOMETER AXIS, AS CONTRASTED WITH THE PREVIOUS REQUIREMENT OF 0.6 DEGREE. THE VALUE IS EMPHASIZED OF HAVING HEADLAMPS AIMED PROPERLY, BOTH FROM THE VIEW POINT OF GETTING BETTER SEEING DISTANCE AT NIGHT AND FROM THE VIEWPOINT OF AFFORDING OTHER DRIVERS NECESSARY GLARE RELIEF.
- Record URL:
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Supplemental Notes:
- No 127, pp 19-22 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:
- Sherman, W F
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Discussers:
- Richards, Oscar W
- Publication Date: 1956
Media Info
- Media Type: Digital/other
- Pagination: 4p
- Monograph Title: Night visibility, 1955
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Serial:
- Highway Research Board Bulletin
- Issue Number: 127
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Design; Drivers; Glare; Headlamps; Low beamed headlamps; Night visibility; Sight distance; Vehicle lighting; Vision
- Geographic Terms: Watts (Los Angeles, California)
- Old TRIS Terms: Driver vision; Low beamed headlights; Sealed beams
- Subject Areas: Design; Highways; Safety and Human Factors;
Filing Info
- Accession Number: 00220380
- Record Type: Publication
- Report/Paper Numbers: HS-023 499
- Files: TRIS, TRB
- Created Date: Apr 21 1994 12:00AM