Experimental studies are conducted for investigating the possibility of automatic driving control systems based on absolute position information. Implementation of such control system requires a methodology of measuring the absolute position, and a control algorithm. In this paper, an accurate and real-time estimation of the absolute position by use of DGPS (Differential Global Positioning System) and sensors on a controlled vehicle is proposed. Automatic steering controller, automatic evasive controller, and a method of relative position measurement of neighboring vehicles are also proposed as application of position information to automatic driving control. Experiments are conducted using sedan-type vehicles. Experimental results validate the proposed estimation and control system, and provide the perspective of enhancing the automatic driving control system by use of the absolute position information.