In this paper, we present a new road traffic monitoring approach for a highway control and management system called RoadGuard. This system copes with several challenges in this type of applications in order to count and track road objects robustly. It adopts a novel approach for tracking road objects, first, to determine continuously their positions on the road, and then it uses vehicle positions to estimate their trajectories. The trajectory analysis provides vital information to control and manage highway traffic. In this paper, our main contribution is a tracking method based on a coherent strategy where both region and object information are used to establish objects correspondence over time. Our method operates in two phases: a spatial analysis that uses a multilevel region descriptors matching in order to identify object interactions and particular object states; and a continuous temporal analysis applied to cope with track management issues. As demonstrated experimentally, the proposed method can detect, track and count road objects accurately in highway videos that include several constraints. In addition, it produces effective and stable road objects tracking.