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Title:

VISUAL PERFORMANCE OF DRIVERS DURING RAINFALL

Accession Number:

00168078

Record Type:

Component

Availability:

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Order URL: http://worldcat.org/issn/03611981

Abstract:

This paper reports an investigation of the effect of rain on the visual performance of drivers. The degradation of static visual acuity in terms of visual angle, detection probability, and legibility as a function of rain intensity was determined by experiments that used a rainfall simulator that produced artificial rain. The significant findings include the following: (a) Water on the windshield is the primary factor accounting for reduced visual performance, (b) visual degradation in the daytime with windshield wipers in operation appears to be a linear function of the rain rate with normal drop sizes, (c) during nighttime conditions, drop size is a significant factor in reducing visual performance (smaller drops are a more serious problem than is the rain rate), (d) wiper speeds above 50 CPM do not improve visual performance, (e) without windshield wipers, visual performace is reduced to levels that are unacceptable for driving (equivalent to visual acuity greater than 20/200) at rain rates greater than 2.5 cm/h (1 in/h), and (f) the effective rain rate can be determined from the vehicle velocity, the terminal velocity of the drop, the rake angle of the windshield, and the actual rain rate. /Author/

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 #:

01411474

Report/Paper Numbers:

HS-022 157

Authors:

Morris, Ron S
Mounce, John M
Button, Joe W
Walton, Ned E

Pagination:

pp 19-25

Publication Date:

1977

Serial:

Transportation Research Record

Issue Number: 628
Publisher: Transportation Research Board
ISSN: 0361-1981

ISBN:

0309026539

Media Type:

Digital/other

Features:

Figures (9) ; References (4) ; Tables (4)

Uncontrolled Terms:

Rainfall intensity

Old TRIS Terms:

Subject Areas:

Highways; Safety and Human Factors

Files:

TRIS, TRB

Created Date:

Jan 30 1978 12:00AM

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