Citation

Stalder HI, Lauer AR. Highw. Res. Board bull. 1954; 89: 70-75.

Copyright

(Copyright © 1954, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

The problem of train-car accidents at night is reviewed. Three theories of experiments were designed to test the efficiency of different types of markings for reflectorizing the sides of boxcars. The hypothesis set up for experimental investigation was: The addition of limited areas of reflectorized material on the side of boxcars has an effect on the discrimination of lateral motion under conditions of mesopic vision. A corollary hypothesis is stated as: The amount and distribution of reflectorized material from the side of boxcars proportionally affects the level of visibility and accuracy of perception of lateral motion. The apparatus used consisted of a dark tunnel approximately 40 feet long with a carriage mounted at the end opposite the subject. Miniature boxcars are mounted on a test belt rotated by a carriage. The boxcars move past an aperture approximately 29 feet from the eye of the observer. Three series of experiments using 30, 30, and 25 subjects, respectively, were run. The following tentative conclusions were reached: (1) the hypothesis set forth for experimental testing was confirmed and the use of materials giving greatest brightness-contrast at night significantly decreases the amount of luminance needed and the difficulty of discriminating movement of boxcars crossing the line of vision at night, (2) the corollary hypothesis is confirmed since the larger the patches of reflectorized material, the lower the level of luminance is needed, (3) the extent of the visual angle reflectorized determines effectiveness up to a certain size, but the limits were not determined, and (4) it appears that for a certain area of reflectorized surface of given reflectance characteristics, larger concentrations of reflectorization would be more effective. further studies should be made of the optimal conditions for size of reflectorized areas, shape of area, spacing distances and height of placement on boxcars for the most effective results