For the instrument panel designer, good visibility means providing clear, legible, and easy-to-understand instruments and controls free from obstructions, shadows, and inadequate lighting. Unfortunately, most of these provisions are subjective in nature and it is ultimately the designer or group of designers who must decide what is “good visibility.”
In order to remove some of this subjectivity, a study was undertaken by Chrysler Corp. to find a more objective approach to measuring visibility. In particular, this study dealt with measuring in a quantitative manner the readability of letter patterns used on instruments, controls, and indicators.
This report, which covers the main results of the study, deals with the effects of such diverse factors as driver age, illumination, and letter size on a driver's perception time-the time it takes for a driver to take his eyes off the road and read a target on his instrument panel.