Real-Time Traffic State Estimation and Prediction for Active Traffic and Demand Management: The Application of DynaTAM

Abstract

Over the last decade, increased interests have been found in the field of Active Traffic and Demand Management (ATDM), and subsequently numerous simulation studies were devoted to see its effectiveness. Unfortunately, the real life benefits of ATDM application are not still apparent. This may be attributable to the following factors: (1) accuracy of traffic data obtained from the available field traffic sensors and failure to transmit the real-time and on-line data to the Traffic Management Centre (TMC); (2) absence of accurate traffic dynamics for the traffic state prediction; and (3) reliable field application software in the field of ATDM. To promise the above functions, in this research, DynaTAM―a field application tool is being developed by the authors. It can be used to analyze, simulate, and optimize traffic network in off-line or on-line mode. This paper presents the framework of DyanTAM and its communication protocol with the outer system, i.e. traffic control devices and field sensors. In the data management module, it has realized a practical data conditioning method which makes it suitable for ATDM application. The current version of this tool provides Variable Speed Limit (VSL) and Ramp Metering (RM) control as the start-up ATDM strategies with a hierarchical and coordinated control system. It evaluates the traffic states for roadway links by the well-known and parsimonious METANET and cell transmission model (CTM). Indeed, these macroscopic traffic models work as reference traffic simulators for traffic state prediction. As a preliminary evaluation, the VSL control module of DynaTAM will be tested this year on the Whitemud Drive (WMD), Edmonton. Therefore, the WMD project will be used in this paper as an exemplification, with some ideas and details given about the field test and application. . Author keywords: Active traffic and demand management; DynaTAM; Variable speed limit; Ramp metering; METANET; Cell transmission model.