Aggregate analysis of driver response to collective route guidance and implications for system control

Variable direction signs (VDS) are widely used in Germany and other European countries as a means to optimally allocate traffic to the limited capacities within highly loaded nested motorway networks. The network effects of such systems, depending greatly on if and how drivers comply, are neither fully understood nor sufficiently taken into consideration in the design of the control strategies. Facing the multivariate problem of route choice behaviour and a lack of appropriate data, oversimplification of driver response prediction is still common practice in most re-routing systems. Extensive work has been undertaken in the area of route choice modelling. Nevertheless, due to the nonmeasurability of the required data the disaggregate models proposed, are of limited applicability in the field of traffic control. It is argued that to represent a viable practical solution, models for the prediction of driver response need to use measurable aggregate data as input. The paper discusses problems associated with the evaluation of the effects of collective re-routing systems and describes a driver response analysis performed using aggregate data for a re-routing system in the Greater Munich area. Results and the approach used for clustering and analysing the aggregate data are described