The report is concerned with the informational load of highway guide signs as indicated by the driver's response delays and faulty lane choices. Fifty experimental subjects individually viewed projected guide signs and after each presentation selected a highway lane leading to a preassigned destination. In one phase of the study, the assigned destination were on the signs; in another the destinations were not on the displays and subjects had to make navigational decisions relating sign information to what they knew about the routes. When subjects searched for destinations actually shown on the signs, lane selection was very rapid. The subject's search probably involved a scanning rather than a reading process. Search for route numbers was found to take longer than search for place names. Subjects required significantly more time to make a lane choice when a navigational decision was required than when the searched for destination was on the sign. Methods were suggested for reducing the informational load of signs.
Abstract