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视觉的机制。因此，首先对货车司机进行坡度认知问卷调查。其次，为了研究视觉环境认知对驾驶动作的影响，对小考生进行了驾驶问卷调查和驾驶实验。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呈直线关系。但另一方面，观测到的速度与对速度的认识之间的关系用对数函数表示。(2)对交通密度和速度的认知关系表现为指数函数。保持足够距离的司机认为密度比速度更重要。另一方面，汽车之间保持小距离的司机分为两类。不重视速度认知的驾驶员，认知与行为不相适应的驾驶员。(3)影响车距的因素不仅有速度，还有个人特征。(4)根据问卷，司机分为三种类型。这些司机认为车与车之间的距离信息很重要，车与车之间的速度差异。(5)约30%货车司机在坡道处有过视错觉。这种体验不仅在高速公路上得到认可，而且在机动车道路上也得到认可。最后，对避免视错觉的措施进行进一步的研究。

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.