Techniques for improving journey time prediction.

The journey time prediction (JTP) system being evaluated by the UK Highways Agency (HA) is designed to provide motorists with real time predictionsof the time it will take to travel to a specific location or road intersection. The system uses live MIDAS data to make a prediction every minute and to display this time to the road user via the message signs. In order to ensure accuracy in a large variety of traffic conditions the system comprises of three complementary predictors, a microscopic motorway simulationpredictor, a simple mathematical based predictor and a steady-state predictor. Each individual system provides a journey time prediction and confidence measure every minute. The output from these predictors is then processed using a moderating function and an optimum prediction determined. Thissystem differs from some other journey time prediction system currently in operation in which the journey time of vehicles entering the journey route is predicted to be the same as for those that have just completed the route. For rapidly varying traffic conditions and long journey durations this approximation is invalid. The use of three predictors, each directly predicting the journey time of vehicles entering the journey route, providesa robust technique for obtaining reliable journey time predictions even under changing traffic conditions. This paper describes two each of the three predictors and gives performance results using MIDAS data. The limitations of the current system are also discussed. The system algorithms underwent an initial assessment and validation phase on the M42 where data was acquired for analysis and optimisation of the predictors. The system operated in the background and did not publish journey time predictions to road users. Now that confidence in the accuracy and reliability of journey timepredictions has been established the intention is to install a fully operational system on the M60 where its performance and the perception of roadusers will be analysed. The assessment phase will investigate the limitations of the system and determine whether the system offers a base to develop further systems which can be used on other critical links in the motorway network. For the covering abstract see E134653.