Abstract
In this study, the legibility of a graphical information board was estimated analytically by CG experiments, and then the factors that prescribe the legibility were extracted and their effects were analyzed. In particular, the study focused on the legibility of map information and a path search. The results showed that it is important to clarify the characteristic elements on an expressway network and the closed loops that compose paths, respectively. The authors confirmed that these factors have an effect on the easiness of route choice under real conditions by an experiment using a driving simulator.