This study aims to develop a shared control system between ADAS and a driver in lateral motion control. The conventional steering assistance systems had a drawback in causing interference between the steering torque from a driver and the steering assistance systems when a large steering assistance level is set. By integrating Direct Yaw-Moment Control (DYC) as an independent control input with the steering assistance, the proposed system can potentially solve the driver-system conflict problem. To investigate the effectiveness of the proposed system, the theoretical and experimental studies by using the driving simulator and the micro-scale electric vehicle were conducted in our previous researches. In this paper, the experimental study by using a normal passenger car in real driving environment is conducted to verify the true effectiveness of the proposed shared control system.