Using automatic vehicle identification and global positioning system 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 estimating current travel times using automatic vehicle identification (AVI) and global positioning system (GPS) data. The proposed algorithm can deduce the travel times on road links either with or without real-time traffic data by integration of real-time and off-line traffic database together. The on-line travel times, in RTIS, are estimated and updated at five-minute intervals based on the real-time traffic data, the off-line travel time estimates, and the simulated and real-time updated variance-covariance relationships between road links. Observation surveys are carried out during different time periods at a selected path in Hong Kong urban area to validate the RTIS travel time estimates. The estimations of travel times on the road segments of the selected path have been conducted with and without using available real-time data. The validation results show that the performance of RTIS is satisfactory and acceptable for both cases.