NCHRP Project 03-97: Traffic Signal Analysis Under Varying Demands And Capacities

KAI lead a team of traffic signal experts in developing a methodology to assess the robustness of signal timing plans under varying demand and capacity conditions. KAI staff gathered data on the variation of demand and saturation flow rates from signal systems in a half dozen different metropolitan areas of the United States. A major data set was provided by the Los Angeles Department of Transportation from their ATSAC system, consisting of 5,300 detectors at 3,400 traffic signals. The data was used to develop demand and capacity profiles for testing signal timing plans. KAI evaluated and developed a measure of robustness for comparing the performance of different timing plans. The methodology was implemented in software to assist users apply the method when using Synchro, TRANSYT, PASSER and other signal timing optimization software.