A Ramp Queue Length Estimation Algorithm

The number of vehicles included in a metered motorway ramp or an urban signalized link at any time is valuable information for real-time control. A Kalman filter is employed to produce reliable estimates of this quantity based on real-time measurements of flow and occupancy provided by three loop detectors. The resulting vehicle-count estimator is tested via microscopic simulation for a variety of metered ramp scenarios and traffic conditions. The simulation investigations indicate a robust estimation performance with low calibration effort needed, which facilitates easy applicability of the method