Abstract
The indoor experiments were carried out to investigate the legibility of the navigation information displayed by in-vehicle navigation devices. In the experiment, the observers are asked to judge whether the destination name is included in the multiple place names or not. Among the series of observer's operation, in order to determine the time required for shifting the line of vision and the time required for accommodation, experimental conditions are established in which the observer moves his line of vision away from distant scenery (5.6 meters to the front) or from nearby scenery (0.75 meters to the front) toward a navigation display device located to the lower left. The reading times were measured and compared under the.~e conditions. Results show that the time for shifting the line of vision ranges between about 0.3 seconds and 0.4 seconds. Regarding the accommodation, for observers in their 20s, accommodation finishes roughly at the same time as completing sift of the line of vision. On the other hand, for the group in their 60s, the accommodation time is longer than the group in their 20s.