Abstract
In-vehicle navigation devices display road maps including place names to provide drivers with such information as their present location, the route to the destination, etc. The authors conduct tests (including both indoor tests and driving tests) to investigate how quickly observers can find the destination name when multiple place names are displayed simultaneously on the screen of the display device. Because the time required to read the information is related to the age of the observer and the number of place names, etc., the authors consider the age of observers and conduct the experiment by varying the number of place names over a range from 6 to 12 place names. Moreover, two types of tests are carried out: those in which the destination name is displayed and those in which it is not displayed. This is carried out in order to investigate how the time required to judge whether the destination name is displayed or not changes. Test results show, for example, that older people require a longer time to read the information than young or middleaged observers.
