Vaya Dinopoulou

Review of road traffic control strategies

Traffic congestion in urban road and freeway networks leads to a strong degradation of the network infrastructure and accordingly reduced throughput, which can be countered via suitable control measures and strategies. After illustrating the main reasons for infrastructure deterioration due to traffic congestion, a comprehensive overview of proposed and implemented control strategies is provided for three areas: urban road networks, freeway networks, and route guidance. Selected application results, obtained from either simulation studies or field implementations, are briefly outlined to illustrate the impact of various control actions and strategies. The paper concludes with a brief discussion of future needs in this important technical area.

Extensions and New Applications of the Traffic-Responsive Urban Control Strategy: Coordinated Signal Control for Urban Networks

The objectives, approach, advantages, and some application results of recent extensions of the traffic-responsive urban control (TUC) strategy are presented. Based on well-known methods of the automatic control theory, TUC allows for traffic-responsive coordinated signal control of large-scale urban networks that is particularly efficient under saturated traffic conditions. The first version of the TUC strategy controlled only the green splits. After initial development and the first field implementations and evaluations, TUC was expanded to perform real-time cycle and offset control, and to allow for public transport priority. Simulation investigations of the extended TUC application in parts of the urban networks of Tel Aviv and Jerusalem, Israel, by use of the AIMSUN microscopic simulator demonstrate the high efficiency of the new signal control strategy.

Applications of the urban traffic control strategy TUC

Despite the long-lasting research and developments in the field of urban traffic control systems, the continuously increasing mobility requirements urge for solutions that will release urban areas from the serious congestion problems and their consequences. From the control point of view, this may be translated into the employment of traffic-responsive systems that respond automatically to the prevailing traffic conditions. This is the aim of the signal control strategy TUC, whose basic philosophy, design methodology, characteristics and application results under both simulated and field conditions are presented in this paper. Based on a store-and-forward type of mathematical modelling and using well-known methodological tools from Automatic Control Theory, the TUC strategy addresses in a simple but efficient way, as demonstrated from the applications so far, the problem of co-ordinated, traffic-responsive signal control in large-scale urban networks.

Simulation investigations of the traffic-responsive urban control strategy TUC

The paper presents the basic characteristics of TUC, a recently developed traffic-responsive urban control strategy. Based on a store-and-forward type of modelling and using well-known methods of the automatic control theory, the approach followed by TUC designs (off-line) and employs (online) a multivariable regulator for traffic-responsive coordinated network-wide signal control. Simulation investigations demonstrate the strategys high efficiency. Summarised conclusions are presented, and future work is outlined.

Application and Evaluation of the Signal Traffic Control Strategy TUC in Chania

The article presents results of a field implementation and evaluation of the traffic-responsive signal control strategy Traffic-responsive Urban Control (TUC) in two junctions of the urban network of Chania, Greece. Based on a store-and-forward modelling of the urban network traffic and using the Linear-Quadratic regulator theory, the design of TUC leads to a multivariable regulator for traffic-responsive coordinated network-wide signal control that is particularly suitable for saturated traffic conditions. The presented results, although limited in space (two junctions) and time of evaluation, are promising for the particular site and for the control of urban networks in general as they indicate a superior performance of TUC compared to an established signal control strategy.

Application of the Signal Control Strategy TUC in Three Traffic Networks: Comparative Evaluation Results

The recently developed network-wide real-time signal control strategy TUC has been implemented in three traffic networks with quite different traffic and control infrastructure characteristics: Chania, Greece (23 junctions); Southampton, U.K. (53 junctions); and Munich, Germany (25 junctions), where it has been compared to the respective resident real-time signal control strategies TASS, SCOOT and BALANCE. The paper describes the three application networks; the application, demonstration and evaluation conditions; as well as the comparative evaluation results. The main conclusions drawn from this undertaking is that TUC is an easy-to-implement, inter-operable, low-cost real-time signal control strategy whose performance, after very limited fine-tuning, proved to be better or, at least, similar to the ones achieved by long-standing strategies that were in most cases very well fine-tuned over the years in the specific networks

Application of the Extended Traffic Signal Control Strategy TUC to the Southampton Urban Road Network

Abstract The paper outlines the objectives and approach along with simulation results of the recent extensions of the traffic signal control strategy TUC (Traffic-responsive Urban Control). Based on well-known methods of the Automatic Control theory, TUC allows for the traffic-responsive coordinated signal control of large-scale urban networks aimed to be particularly efficient under saturated traffic conditions. Simulation investigations of the extended TUC application in a large part of the urban network of Southampton, UK, by use of the METACOR microscopic simulator, demonstrate the efficiency of the new signal control strategy.