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This project involved a detailed review of coordinated metering algorithms currently operating in the United states and a simulation analysis to examine the performance of three algorithms that represent each coordination approach; the Denver incremental coordination, the Seattle Fuzzy metering and the Minnesota explicit section-wide coordination approaches. Researchers used a macroscopic simulation model with the same geometry and traffic demand conditions. Based on the analysis results, they developed alternative metering approaches by combining conventional zone-wide control with fuzzy coordination. They also developed two new alternative procedures to estimate bottleneck capacities in real time; an adaptive estimation method using Kalman Filter and a neural-network based approach that predicts traffic volume for a given mainline location using traffic data collected from upstream and downstream detectors. Both approaches were tested with the real data collected from the sample freeway sites. The preliminary test for alternative strategies using simulation with an example freeway in Minnesota showed promising results in terms of reducing congestion and increasing throughput on the mainline. Further testing and research is recommended.

A corridor simulation environment with the capability of modeling various types of traffic control strategies as external control modules is critically important in developing and improving corridor management strategies. In this research, a microscopic network simulation model, Vissim, is used to develop such an environment. The new stratified Minnesota Department of Transportation metering algorithm was simulated using the 169 freeway, and its performance was compared with that of the fixed-metering method. Based on that analysis, an alternative approach to determining each entrance ramp's minimum metering rate was developed and coded, as well as an adaptive approach to automatically coordinating a freeway meter with the adjacent intersection signal. The results clearly show the advantage of reducing the overall delay at the ramp-intersection area, while producing 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 can be used for future studies, including the continuous enhancement of the stratified metering algorithm to take advantage of the maximum allowable wait 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. Note: The Phase I report is available at https://hdl.handle.net/11299/856.