Abstract
The effects of age, display direction, arrangement of switches and number of layers
on performance to the design of display and control systems were discussed. A dual-task experiment
was conducted in which the primary task was first-order tracking. The secondary tasks included
control of an air conditioner, the operation of a radio, and the operation of a CD/MD, by means of a
steering wheel mounted switch. The display was arranged either in front of a participant. As
predicted, age affected the performance measures. As for the young adults, the task completion time
did not differ significantly among one-, two-, and three- layered conditions for both horizontal and
vertical displays, and for both vertical and horizontal arrangements. The performance of older
adults was affected by display condition, layer condition, and arrangement of switches. As for the
completion time of secondary switch-pressing task, age by switch arrangement interaction, age by
number of layers of display structure interaction, age by switch arrangement by number of layers
interaction, and age by display direction by number of layers interaction were significant. Such
results should be taken into account when designing display and control systems in man- vehicle
systems.
Keywords - display direction, arrangement of steering wheel mounted control, number of layers,
man-vehicle system, aging.