Several predictions have been made of the time savings which might be achieved by users of dynamic route guidance. Until recently, the lack of actual systems has made it difficult to check the accuracy of such predictions, moreover, the design of surveys to isolate the benefits from other causes of travel time differences between drivers is not straightforward. We developed a method for doing so in an earlier desk study for TRRL. The recent LISB dynamic route guidance pilot project in Berlin provided an opportunity to develop the method further, test it in practice, and obtain estimates of the savings achievable. The experimental design permitted an assessment of travel time differences when experienced and inexperienced drivers used LISB, for peak and off peak journeys, and for different days of the week. The method was broadly successful, but lessons were learnt which would enhance any future application of the same experimental procedure. The results showed substantial differences in routes taken with and without LISB, and some indications of route changing as the inexperienced drivers learned from using LISB. However, the overall travel time savings from using LISB were small. The only significant saving was for experienced LISB users, when compared with inexperienced drivers not using LISB. In this paper the method adopted is presented, performance assessed in practice, results presented and the implications for the future development of dynamic route guidance discussed.
Samenvatting