Knowledge that Transforms

The relationship between recognition threshold and degree of elongation of letters used in road pavement messages was investigated. Experiments were conducted in the laboratory and in a field situation. It was found that in both situations the normally proportioned letters were recognized at smaller visual angles than the more elongated letters; increases in letter elongation did not produce increases in recognition distance directly proportional to the increases in the vertical visual angle subtended. Mathematical models based on the relationship between preceived and real distance largely describe the observed effect, and a formula is given by which traffic engineers can calculate the necessary degree of letter elongation for a desired threshold recognition distance.

The purpose of this study was to investigate the effects of crash helmet visor color on color recognition. Sixty subjects were asked to report whether a series of slide presentations contained red, yellow, green, or none of these colors. The subjects viewed the slides through either a colored crash helmet visor or a clear helmet visor. The visor colors used were blue, green, orange, smoke, and yellow. The results showed that the colored visors increased the number of color recognition errors. Restricted use of colored visors is advised. /Author/