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Title: VISIBILITY OF CIRCULAR TRAFFIC-SIGNAL INDICATIONS
Accession Number: 00345314
Record Type: Component
Availability: Find a library where document is available Abstract: An empirical determination of traffic signal visibility is presented. The study used subjects seated in stationary vehicles viewing standard, full-sized traffic-control signals at distances ranging from 370 to 1300 ft. Data, including response accuracy and response latency, were collected for both day and night ambient lighting conditions. It was found that currently used circular traffic-signal indications are generally adequate for nighttime service but their adequacy for daytime conditions is suspect. Signal visibility was found to be somewhat insensitive to signal lens size and illumination intensity for nighttime operations, which implies that even the dimmest signal tested (8-in lens with 67-W bulb) is above threshold visibility for all distances at night. The single most important factor affecting the visibility of traffic signals during the day is signal color. Green indications generally led to the poorest subject response, in terms of both response accuracy and response time, for the daytime observations. In relation to visibility considerations alone, the data obtained present strong support for the possibility of dimming all colors of 12-in signal indications at night. (Author)
Supplemental Notes: Publication of this paper sponsored by Committee on User Information Systems. 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.
Monograph Accession #: 00362058
Corporate Authors: Transportation Research Board 500 Fifth Street, NW Authors: King, Gerhart FPagination: pp 7-14
Publication Date: 1981
Serial: ISBN: 0309032520
Media Type: Print
Features: Figures
(4)
; Maps
(1)
; References
(12)
; Tables
(5)
TRT Terms: Old TRIS Terms: Subject Areas: Highways; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure
Files: TRIS, TRB
Created Date: Jan 29 1982 12:00AM
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