A Basic Study on the Mechanism of Illusory Vision at the Slope on Expressway

本研究的目的是探讨错觉的机制。为此，首先对货车驾驶员进行了斜坡认知的问卷调查。其次，通过对小型驾驶员的问卷调查和驾驶实验，探讨视觉环境认知对驾驶操作的影响。所得结果总结如下。(1)观测到的交通密度（每米车辆数）与驾驶员对交通密度的认知之间存在直线关系。但另一方面，观察到的速度和对速度的认知之间的关系由对数函数表示。(2)交通密度认知与交通速度认知呈指数函数关系。与汽车保持足够距离的司机认为密度比速度更重要。另一方面，与汽车保持小距离的驾驶员分为两种类型。这些驾驶员是不重视对速度的认知，以及认知与行为不一致的驾驶员。(3)影响汽车之间距离的因素不仅是速度，而且是个人特征。(4)根据问卷调查结果，将驾驶员分为三种类型。那些认为汽车之间的距离，汽车之间的速度差以及两者的信息都很重要的驾驶员。(5)约有30%的货车驾驶员在斜坡上有过视错觉。最后，本文还对如何避免视觉错觉的措施进行了进一步的研究。

The purpose of this study is to discuss the mechanism of illusory vision. Therefore, firstly the questionnaires on the cognition to the slope were conducted for truck drivers. Secondly in order to investigate the effect of the cognition to visual environments on driving maneuver, the questionnaires and experiments with driving were conducted for small examinees. The obained results are summarized as follows.(1) There is a straight-line relationship between the observed traffic density (vehicles per meter) and drivers'the cognition to traffic density. But on the other hand the relationship between the observed speeds and the cognition to speeds is represented by a logarithmic function.(2) The relationship between the cognition to traffic density and velocity is presented with exponential function. Drivers who keep enough distance between cars think importance to density than velocity. On the other hand, drivers who keep small distance between cars are divided into two types. Those are drivers who do not think importance to the cognition to velocity, and drivers whose the cognition and behavior do not correspond.(3) The factors that influence the distance between cars are not only velocity but also personal characteristics.(4) According to the questionnaires drivers are divided into three types. Those are drivers who think importance to the information of the distance between cars, the deference of velocity between cars and both.(5) About 30% truck drivers have experienced illusory vision at the slope. The experiences are recognized not only expressway but also motor-vehicle way.Finally further study on the measures to avoid illusory vision will be carried out in the future.