LEGIBILITY AND BRIGHTNESS IN SIGN DESIGN
AN IMPORTANT BUT NEGLECTED ASPECT OF SIGN DESIGN IS THE CHOICE OF LETTER HEIGHTS TO SATISFY NIGHTTIME LEGIBILITY REQUIREMENTS. IN CHOOSING LETTER HEIGHTS, THE FUNDMENTAL RELATIONSHIP OF BRIGHTNESS AND LEGIBILITY MUST BE TAKEN INTO ACCOUNT. SIGN BRIGHTNESS IS A FUNCTION OF MANY FACTORS INCLUDING SIGN MATERIAL AND POSITION, ROAD ALIGNMENT, AND VEHICLE AND HEADLIGHT CHARACTERISTICS. A COMPUTER PROGRAM WAS DEVELOPED THAT INCORPORATES THESE FACTORS AND DETERMINES SIGN BRIGHTNESS AS A FUNCTION OF ROAD DISTANCE. THE DISTANCE AT WHICH THE SIGN MUST BE FIRST LEGIBLE IS USED IN CONJUNCTION WITH THE COMPUTED BRIGHTNESS AND PUBLISHED EMPIRICAL DATA RELATING BRIGHTNESS TO LEGIBILITY TO CALCULATE REQUIRED LETTER HEIGHTS. MINIMUM LETTER HEIGHT REQUIREMENTS FOR ROAD DISTANCES UP TO 2,000 FT ARE PRESENTED. THE CASES REPORTED INCLUDE A STRAIGHT ROAD, HIGH AND LOW HEADLIGHT BEAMS, SIX SIGN POSITIONS, FOUR HORIZONTAL ALIGNMENTS, AND FOUR VERTICAL ALIGNMENTS. FOR NIGHTTIME LEGIBILITY, IT WAS FOUND THAT REQUIRED LETTER HEIGHTS ARE MUCH LARGER THAN THE 50-FT-PER-IN. RULE INDICATES. BECAUSE OF THE WIDELY VARYING SIGN BRIGHTNESS FOUND IN ACTUAL ROADWAY CONDITIONS, EACH SIGN SHOULD BE TREATED INDIVIDUALLY AS A SEPARATE DESIGN PROBLEM. /AUTHOR/
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Availability:
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Supplemental Notes:
- Sponsored by Committee on Traffic Control Devices and presented at the 50th 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:
- Adler, Bernard
- Straub, Arthur L
- Publication Date: 1971
Media Info
- Media Type: Print
- Features: Figures; References;
- Pagination: pp 37-47
- Monograph Title: Traffic control and driver information
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Serial:
- Highway Research Record
- Issue Number: 366
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Alignment; Brightness; Computer programs; Design; Height; Legibility; Lettering; Night; Night visibility; Numbers; Sight distance; Traffic signs; Visibility
- Old TRIS Terms: Letters
- Subject Areas: Design; Highways; Operations and Traffic Management;
Filing Info
- Accession Number: 00226187
- Record Type: Publication
- ISBN: 0309019818
- Report/Paper Numbers: HS-011 999
- Files: TRIS, TRB
- Created Date: Mar 20 1972 12:00AM