This paper describes the development of the obstacle sensing and collision avoidance for Adaptive Cruises Control(ACC) system with an automated vehicle using the laser scanner and RTK - DGPS(Real Time Kinematic - Differential Global Positioning System) system for autonomous navigation. The real scale vehicle for experiment is constructed using RTK-DGPS and laser scanner. Laser scanner is detects the obstacle of the vehicle front. The controller applies to RTK-DGPS and laser scanner based real scale autonomous vehicle, and the performance of the controller and the results of experiments are suggested.