Search Content

This report summarizes the final results of the enhancement and validation of the control-emulation method in the real freeway environment. A computer-based control-emulation method that can evaluate various automatic rate-selection strategies was developed by this research team in the previous phase of this research. Software was developed that operationalizes this method for field applications. A method was developed and tested to determine the best metering thresholds for a given section of a freeway, under normal weather conditions, using the control-emulation method and the downhill simplex optimization procedure. The method finds the optimal thresholds for each ramp in a given. section of the freeway by considering the system-wide traffic conditions. An independent procedure to determine the initial thresholds that can be used to initialize the optimization process was also developed. A preliminary study for developing an on-line predictor for freeway exit demand was performed and an adaptive prediction procedure was developed. The prediction model formulated in this research used historical demand and current day measurements. Further, the parameters in the prediction model are updated in real time using the Extended Kalman Filter, so that the propagation of prediction error can be minimized.