Evaluation of Travel Time Prediction Products

Virginia Department of Transportation (VDOT) displays real-time travel times to various destinations on many of its changeable message signs. These travel time data are purchased from a private sector provider, and are based on measurements of instantaneous speeds along each segment of roadway between the changeable message sign and the posted destination. These measurements are taken immediately before posting, and therefore reflect current conditions. When travel times are displayed for long distances, they may be different than those experienced by motorists, as downstream traffic conditions often change during the course of a trip. Several private sector providers offer travel time predictions, in which travel times are predicted from a combination of real-time speed measurements, historical speeds, and predictive models. This study will evaluate the accuracy of travel time predictions from a private sector provider as compared to the provider’s real-time measurements of the same corridors.