American Scientist

To the Editors:

On reading Henry Petroski's article "On the Road" (Engineering, September-October 2006) I was reminded of a pet complaint I have had for years regarding stop signs.

Some years ago, as noted in this article, these signs were yellow with black lettering which were plainly visible under most conditions. Now they are red with white letters. At night, or when they are in front of vegetation, these red signs tend to blend into the background and nearly vanish. Add to this the problem that about 10 percent of men, such as myself, are somewhat color-blind, and red-green is the most common deficiency. This article discusses the study and tests that were made of the comparative legibility of the typeface used on the Federal Highway Administration  Interstate signs. I wonder, has any study been made comparing the legibility of yellow versus red stop signs?

But the problem may have been solved. In my area many signs have been installed, warning drivers that they are nearing school zones, traffic lights, etc.—and stop signs. These warning signs are diamond shaped and, of course, for good visibility the color is bright yellow.

Charlie A. Crutchfield
La Crescenta, CA