Abstract-This paper presents a system whose aim is to detect and classify road obstacles, like pedestrians and vehicles, by fusing data coming from different sensors: a camera, a radar, and an inertial sensor. The camera is mainly used to refine the vehicles' boundaries detected by the radar and to discard those who might be false positives; at the same time, a symmetry based pedestrian detection algorithm is executed, and its results are merged with a set of regions of interest, provided by a Motion Stereo technique.The tests have been performed in several environments and traffic situations, their results showed how the vision based filtering provides an effective reduction of radar's false positives; furthermore, the regions of interest detected by the Motion Stereo algorithm, truly improves the pedestrian detector's performance again by keeping low the number of detection errors.The system has been shown during the APALACI-PReVENT European IP final demonstration 1 in September 2007 in Versailles (France).