Guidelines for Determination of Optimal Traffic Responsive Plan Selection Control Parameters

Closed-loop traffic control systems can be operated by either Time-of-Day (TOD) mode or Traffic Responsive Plan Selection (TRPS) mode. When properly configured, the TRPS mode has the potential to provide an optimal operation due to its ability to accommodate abnormal traffic conditions such as incidents, special events, and holiday traffic. TRPS mode can also reduce the need for frequent redesign/updates to signal timing plans. To date, there have not been any formal guidelines for selection of robust and optimal TRPS system parameters and thresholds. Consequently, traffic engineers usually revert to the TOD mode of operation for its ease of setup. This report provides a new methodology for robust and optimal selection of TRPS parameters and thresholds. The report presents an innovative framework of TRPS system setup following a comprehensive approach that incorporates a multi-objective evolutionary algorithm and a supervised discriminant analysis. The developed guidelines are presented in simplified tables to facilitate their implementation. Guidelines were verified by using hardware-in-the-loop simulations. Compared to just the worst possible solutions encountered during the optimization, the final solution provided a concurrent savings of 53% in delay and 19% in stops.