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Title:

INDIRECT FACTORS AFFECTING REFLECTIVE SIGNS BRIGHTNESS (ABRIDGEMENT)

Accession Number:

00163042

Record Type:

Component

Availability:

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Order URL: http://worldcat.org/isbn/0309025877

Abstract:

The design is outlined of an experiment which simulated volumes of 300, 600, and 1,500 vehicles/lane/h on a test road. All vehicles in all tests employed low-beam head lamps since common use of lower beams is well documented and is the rule with high volumes. The study found that for unlighted overhead signs, the single vehicle with low beams produced luminances of 3.4 to 6.9 cd/m sq (1 to 2 ft-L). With 3 vehicles spaced at 152-m (500 ft) increments, sign luminance for the test vehicle increased from 3.8 to 9.6 cd/m sq (111 to 2.8 ft-L). With 6 vehicles spaced at 91-m (300-ft) increments, sign luminances for the test vehicle increased from 9.3 to 14.0 cd/m sq (2.7 to 4.1 ft-L). For 15 vehicles spaced at 5-m (50 ft) increments, corresponding to near capacity for an average facility, sign luminances for the test vehicle increased from 26.7 to 28.4 cd/m sq (7.8 to 8.3 ft-L). The improvement noted at longer distances is due to the close angular proximity of the adjacent headlights. For shoulder mounted signs, lower beam sign luminances were 13.7 to 54 cd/m sq (4 to 16 ft-L) with reflective sheeting material for a signle car. During the experiment with 15 cars, it was found that for all materials and distances, an average of 19 percent of the sign luminance comes from the driver's head lamps. The measurements made in rainfall conditions displayed higher luminances.

Supplemental Notes:

Publication of this paper sponsored by Committee on Visibility. 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 #:

01410993

Report/Paper Numbers:

HS-021 004

Authors:

WOLTMAN, H L
Youngblood, W P

Pagination:

p. 35-37

Publication Date:

1976

Serial:

Transportation Research Record

Issue Number: 611
Publisher: Transportation Research Board
ISSN: 0361-1981

ISBN:

0309025877

Features:

Figures (3) ; References (2) ; Tables (2)

Old TRIS Terms:

Subject Areas:

Highways; Materials; Safety and Human Factors

Files:

TRIS, TRB

Created Date:

Oct 13 1977 12:00AM

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