Abstract
This study grasps the merging part of expressway from the upstream section, focuses on the deceleration behavior of the main line vehicle, and examines the deceleration beginning point and its factors. First, the distribution of the deceleration beginning point in the main line vehicle was acquired using the data from the indoor experiment with a driving simulator. And, the relation among the deceleration beginning point, the point where subjects began staring the confluence car, and the distance between two cars was analyzed. Those results showed that the factors influence the deceleration behavior at the merging part have the possibility of the point where subjects began staring the confluence car, the distance between two cars, and the intention of the driver who gives way to the confluence car
