The accuracy of the travel time information has a direct bearing on how the user prepares or adjusts his schedule, and since the user can verify the accuracy of the data himself it is clear that there is a strong demand for the information's accuracy. Therefore, it is important to assess the operation of the travel time information service that is currently being provided in order to build the consumer's trust in the service and to let him make an appropriate choice of traffic action. For this reason, it was felt that an assessment of the accuracy of the presently supplied information might be the first step towards the provision of a suitable information service. The results have demonstrated that approximately 80% of the information is within the allowable error margin demanded by the user and that the required accuracy can thus be assured on a reasonable scale. The remaining 20% or so of the information provided exceeds the required accuracy limit. The errors associated with this part of the information tend to occur when there are particularly sharp changes in traffic conditions. In fact, however, the demand for time information is the greatest when such abrupt changes in traffic flow occur. In view of this it is clearly imperative that the accuracy of information be improved especially under these conditions.
Abstract