00163039

Component

http://onlinepubs.trb.org...s/trr/1976/611/611-002.pdf

https://scholar.google.co...rbes&publication_year=1976

A laboratory study of sign legibility has shown that a contrast of between 30 and 50 percent is required to maintain 75th percentile legibility. Legibility distance increased gradually with greater contrast to about 80 percent; above a luminance ratio of 5 to 1, legibility did not increase greatly. As ambient levels increased, legibility distance increased linearly with the logarithm of either the letter or the sign luminance, whichever was greater. Five color combinations were measured. This report gives additional results on color recognition and applies the effects of luminance and contrast to legibility distance for 11 color combinations, after corrections were made for letter and stroke, width. A method for estimating legibility was developed for black and white letter and sign combinations. The effects of luminance and contrast on color recognition at five ambient levels showed the need to increase luminance and contrast as ambient levels increase. Laboratory luminance data, confirmed by two sets of outdoor measurements, furnished a basis for determining the luminance ratios used in the legibility estimates. A basis for estimating glance legibility distance in relation to ordinary legibility (long viewing time) is suggested. /Author/

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

01410993

HS-021 004

pp 17-24

1976

Transportation Research Record

0309025877

Print

Figures (5) ; References (8) ; Tables (1)

Brightness; Color vision; Contrast; Distance; Highway safety; Laboratory studies; Legibility; Traffic signs

Highways; Safety and Human Factors

TRIS, TRB

Oct 13 1977 12:00AM

• COMPARISON OF DRIVER DYNAMICS WITH ACTUAL AND SIMULATED VISUAL DISPLAYS
• DRIVER REACTION TO IMPROVED WARNING DEVICES AT A RURAL GRADE CROSSING (ABRIDGEMENT)
• EFFECT OF ILLUMINATION ON RURAL AT-GRADE INTERSECTION ACCIDENTS (ABRIDGMENT)
• EFFECTIVENESS OF AUTOMATIC WARNING DEVICES IN REDUCING ACCIDENTS AT GRADE CROSSINGS
• EVALUATION OF HIGH-INTENSITY SHEETING FOR OVERHEAD HIGHWAY SIGNS
• INDIRECT FACTORS AFFECTING REFLECTIVE SIGNS BRIGHTNESS (ABRIDGEMENT)
• INVESTIGATION OF ACCIDENT DATA FOR RAILROAD-HIGHWAY GRADE CROSSINGS
• OVERHEAD SIGNS WITHOUT EXTERNAL ILLUMINATION
• PASSIVE CONTROL AT RAILROAD-HIGHWAY GRADE CROSSINGS (ABRIDGEMENT)
• PREDICTING TARGET-DETECTION DISTANCE WITH HEADLIGHTS
• REVIEW OF NEEDS OF USERS OF RIDE QUALITY TECHNOLOGY (ABRIDGEMENT)