MONITORING OF TRAFFIC DENSITY PROFILES USING MEASUREMENTS FROM LOOP DETECTORS AND VEHICLE TRIP DATA

A freeway road section monitoring scheme is presented for a mixed information basis using both loop detectors and vehicle trip data. The approach taken is the model-based estimation scheme of the Extended Kalman Filter which is adapted to this problem. Since vehicle trip data like section travel time or the driven speed profile refer to different time instances in the past, special measures have to be taken to make the Kalman Filter formalism applicable. It is shown by simulation results that vehicle trip data can be rather helpful to increase the reliability and accuracy of the estimated section load profile, particularly in critical situations of congestion.