Abstract
We studied the maneuverability of in-vehicle touch panel hierarchical menus. As the number of response increases, the required time to obtain the goal increases. So an increase in depth or breadth increases the goal acquisition time. We tried to investigate the tradeoff between these two variables. The experiment to acquire the goal was performed using our driving simulator. Breadth (the number of choices) varied from two to sixty-four, while depth (the number of menu levels) varied from one to six. As a result four different hierarchical combinations b2^d6,b4^d3,b8^d2,b64^d1 are possible. Based on the goal acquisition time, in-car glance time, deviation from traffic lane, error rate and evaluation of subjects, B4^d3 was found to be the best for in-vehicle touch panel followed by b8^d2.
