Metrology of vehicles trajectories has several applications in the field of road safety, particularly in dangerous curves. Actually, it is of great interesting to observe the trajectory of vehicles with the aim of designing a real time driver warning device in these areas. The best contribution of this paper is a multi-sensors system which has been totally developed for the French project SARI and can record three cameras VGA and rangefinder information's. This system can measure the trajectories of each vehicle on one hundred meter long curve. Also this article presents a probabilistic method of accurate vehicles tracking, using a particle filter, a kinematic model close to reality, known as bicycle, and the definition of an observation function based on the reprojection of simplified 3D models of vehicles. A detailed study of the trajectories parameters allow to extract the abnormal drivers' behaviours and then to better understand the drivers' actions.