TRAVEL-TIME ESTIMATION IN THE GERDIEN PROJECT

In order to produce traffic predictions up to Ih ahead for a motorway network, it is essential to produce reliable estimates for the travel time over motorway sections, This article describes a model for estima ting travel times on motorway sections 3-5 km in length, The model use s measurements from inductive loop detectors and is based on a linear input-output ARMA model representation. The model is evaluated using r esults from a field study. The evaluation data set covers traffic situ ations with both 'normal' congestion and congestion due to accidents o r incidents, The observed and estimated travel times are very close in cases of normal congestion. Travel time estimates in cases concerning accidents showed large deviations, but in these cases there were no t ravel time observations to verify their accuracy.