Using automatic vehicle identification data for travel time estimation in Hong Kong

This paper presents a Real-time Traveler Information System (RTIS) for Hong Kong, in which a novel solution algorithm is proposed for estimation of both the current and instantaneous travel times using automatic vehicle identification (AVI) data. The proposed algorithm also deduces the travel times on the other road links without real-time AVI data, By integration of the filtered real-time and off-line database together, the RTIS can provide area-wide traffic information in the whole network of Hong Kong. The travel time estimates are updated once every five minutes in the RTIS. Observation surveys are conducted during different time periods at a selected path in Hong Kong urban area to validate the RTIS travel time estimates. With the use of the same set of observation data, comparison is also given to the estimation results of the other three existing AVI travel time estimation algorithms: TransGuide, TranStar and Transmit algorithms in US. It was found that the proposed RTIS algorithm could generate the current travel time estimates for the three study periods with the minimum absolute errors and absolute percentage errors. The estimations of instantaneous travel times on the road sections with and without real-time AVI data have also been illustrated. The validation results show that the performance of RTIS is satisfactory and acceptable.