, Professor, UMD-Civil Engineering
Corridor simulation with the capability of modeling various types of traffic control strategies as the external control modules is critical to developing and improving corridor management strategies. In this research, a microscopic network simulation model, VisSim, was used to develop such an environment. The new stratified Mn/DOT metering algorithm was simulated using U.S. Highway 169; its performance was compared with those of the fixed-metering method.
Based on the analysis results, an alternative approach to determine the minimum metering rate for each entrance ramp was developed and coded. Further, an adaptive approach to automatically coordinate a freeway meter with the adjacent intersection signal was also developed and evaluated using the corridor simulation environment. The evaluation results (with a sample network consisting of one intersection and one entrance ramp) show a clear advantage of the proposed method in reducing the overall delay at the ramp-intersection area. In addition, the method produced higher or compatible total vehicle-miles compared with the conventional intersection-control methods, i.e., pre-timed and actuated, without employing ramp metering. The corridor evaluation environment developed in this study can be used for future studies, including the continuous enhancement of the stratified metering algorithm to take advantage of the maximum allowable waiting time, automatic identification of the most effective metering strategy depending on prevailing traffic conditions, and extension of the adaptive coordination method to multiple intersections adjacent to a freeway entrance ramp.