Travel time advantages by dynamic route guidance (DRG) in Germany: status quo and improvement potential.

Dynamic Route Guidance Systems shall primarily serve to reduce travel time. Whether and to what extend this benefit can actually be made is ambiguous for practical applications. Based on these considerations and the associated data, travel times and routes by Static and Dynamic Route Guidance on selected journeys are compared. The estimated travel time as calculated by the vehicle and the actual travel time using the current traffic message quality are generated and stored. Finally the selected journeys are onceagain investigated under the assumption of optimal traffic message quality. The resulting travel times are compared with the above results and the improvement potential is derived. In order to obtain valid results, simulations are made for the period of a whole year. The users under consideration are commuters, who have regular journeys to and from their place of work. Because traffic messages are only available area-wide for highways the study is limited to this road network. Also it is assumed that the networkcontains a low number of cars equipped with Dynamic Route Guidance Systems. The analysis of traffic message quality in the Stuttgart region offers an actual quality value of 35 percent. This means that only 35 percent of the traffic messages correctly represent an incident situation within the given limitations of this study. Further calculations with variable traffic message quality (varying from 35 to 100 percent) show, that the previousresults can be improved by enhancing the message quality. A quality enhancement from today's 35 to 100 percent (optimal information) can realise a threefold improvement in travel time savings. In the areas of Rhine-Ruhr and Rhine-Main, time savings of up to 15 percent are achievable for dynamically guided commuters. Because of the declining interrelationship between time saving and message quality, it is sufficient to enhance the message quality from today's 35 percent to 70 percent in order to achieve 95 percent of the possible maximum saving potential. In the high density areas thischange averages up to 15 percent time savings. Finally it is to be noted that an extension of this study regarding further user groups and network classes should be aimed to gain more differentiated results in these fields and to include the problem of missing traffic messages in most network layers. For the covering abstract see ITRD E135582.