HUMAN FACTORS REQUIREMENTS FOR REAL-TIME MOTORIST INFORMATION DISPLAYS. VOLUME 9. A STUDY OF PHYSICAL DESIGN REQUIREMENTS FOR MOTORIST INFORMATION MATRIX SIGNS

The purpose of this study was to identify the physical design requirements of changeable message lamp matrix signs. Design characteristics addressed include sequential and run-on displays, message length, words per line, number of lines, display rates, legibility, bulb loss, and symbolic substitution. Effects of driver workload were also addressed. The studies were conducted first in a laboratory equipped with a rear projection screen and subject response controls. Slides and motion picture film were used with controlled exposures to obtain subject responses. Percent correct response was the evaluation criterion for all variables except symbolic substitution which related to association. Selected laboratory results were subjected to limited field validation in a controlled driving environment. The field studies considered subject performance under both "unloaded" and "loaded" conditions.