Traffic management measures aim for improvement of passive and active safety and reduction of congestion and emissions. Therefore knowledge on road vehicle behavior and traffic flows is required. In this paper we present a system that monitors road traffic using cameras alongside the road. The system is able to classify and track vehicles over 100 meters using a single camera with high accuracy on different types of roads in different types of weather. By combining multiple cameras individual vehicles are tracked over more than one kilometer. From the trajectories information about individual vehicles, vehicle interactions and traffic flow is extracted. This data can then be used for traffic management research questions. The ambition for the future is to optimize the system for real-time usage in cooperative driving application, incident detection, real-time traffic information, active safety applications and infra-to-vehicle communication.