Development of Freeway Active Traffic Control System

Abstract

Currently, the world is suffering from daily recurrent traffic congestion. Traffic engineers have developed the ATDM control system as a countermeasure to mitigate the problem of traffic congestion using various active control measures. In 2011, the City of Edmonton initiated a study to develop an integrated active traffic control system targeted at improving the efficiency of traffic operations on a major freeway corridor around Edmonton. The Dynamic Traffic Analysis and Management (DynaTAM) control system has been designed to implement the integrated control through RM (Ramp Metering) and VSL (Variable Speed Limit). DynaTAM is a Model Predictive Control (MPC) based pro-active traffic control system. In this paper, the control framework of DynaTAM is presented in brief. The continuously growing number of auto vehicles on our roadways causes serious traffic problems around the world on an everyday basis. Daily recurrent congestion on freeways leads to a significant loss in mobility as well as increased energy consumption and emissions. Moreover, previous studies have proved that as the result of congestion, unstable traffic flow could lead to higher incident potential. To mitigate traffic congestion as well as congestion-related crashes, the most important development in recent transportation management research is the concept of Active Traffic Management (ATM). One major approach to the implementation of ATM is through traffic prediction models based on pro-active traffic control systems. In 2011, the City of Edmonton initiated a study to exam the feasibility and performance of implementing integrated active traffic management in Edmonton, AB (Canada). The study is targeted at improving the traffic operations along a major highway corridor in Edmonton, which is suffering from daily recurrent traffic congestion. In this study, the control algorithm DynaTAM (Dynamic Analysis Tool for Active Traffic and Demand Management) is proposed to perform the prediction based on integrated and coordinated optimization control using both RM and VSL. Based on a macroscopic traffic flow model, the proposed DynaTAM control framework considers the correlations of integrated control measures and determines the control plan for both RM and