Real-time travel time estimation using automatic vehicle identification data in Hong Kong

This paper proposes a real-time traveler information system (RTIS) for estimating current travel times using automatic vehicle identification (AVI) data in Hong Kong. The current travel times, in RTIS, are estimated by real-time AVI data, the off-line travel time estimates and the related variance-covariance relationships between road links. The real-time AVI data adopted for RTIS are Autotoll tag data in Hong Kong; whereas the off-line link travel time estimates and their variance-covariance matrices are obtained from a traffic flow simulator. On the basis of integration of these real-time and off-line traffic data, the current traffic conditions on Hong Kong major roads can be estimated at five-minute intervals. A case study is carried out in Kowloon Central urban area to collect observed data for validation of the results of the proposed RTIS.