Abstract
The effect of painting color gradation in reducing the resistance to the inflow of vehicles into the tunnels has been discussed in the past study. However, the influence of the painting with a reverse-course gradation has not been evaluated yet. This paper describes results of mental-evaluate experiments, conducted by using CG and video images. The subject of the discussion are tunnel portals, which was redesigned by painting with a nominal and a reverse-course gradation in order to reduce the resistance and consider the landscape. The study indicates the relation between the resistance to the inflow and the congenial driving environment. Moreover, it has shown the effectiveness of the redesign by painting with a reverse-course gradation.
