One way to provide dynamic route information to travellers is by means of Variable Message Signs (VMS). Owing to the availability of reasonable alternative routes for several important traffic relations, the Ring Road around Amsterdam, which was completed in September, 1990, offers an almost ideal situation for the use of VMS. The first VMS will be installed on this Ring Road by the end of 1991. In this paper results of research into the design and the effects of a VMS will be presented.The paper starts with the description of the general framework of a VMS-system. Several projects related to aspects of this framework are discussed in more detail: A simulator study into the effects of VMS on route choice and driving behavior. The influence of VMS on route choice and driving behavior was studied using a mock-up car. Several types of VMS were used for providing route information. Recommendations for a persuasive design of a VMS are given, based upon the relation between the design and the moment of diversion. A stated preference investigation into route choice behavior. A literature review showed that hardly any literature is available in which the trade-off between time, distance and congestion (the three most important factors in route choice behavior on a motorway system) is established for the case of congested networks. Therefore, a study on the trade-off between distance and congestion in congested networks was conducted. Using stated preference techniques 200 commuters frequently encountering congestion, were questioned. On average, a commuter appears to be willing to diverge 12.4 km for every 10 minutes of congestion delay. Simulation of traffic flows under provision of dynamic route information to travellers by means of VMS. In this study the traffic flow on the Ring Road around Amsterdam was simulated using a Contram-like model. Several traffic scenarios were evaluated, including scenarios where a VMS is used to guide the traffic. It is concluded that the provision of information to travellers concerning their best route can greatly improve the performance of the traffic system. However, under certain conditions, the use of VMS can lead to a reduced performance of the total traffic system (measured in hours of travel, distance travelled and total energy consumption). Recommendations for the design of a VMS- system are given, based upon the results of the various studies.