Intelligent transport system
Traffic information system: a case study
Development of a Traffi c Information System (TIS) providing near-real time traffi c status information is a case study for deployment of utilisation of location-related data embedded in mobile communication networks. The accurate traffi c status estimation requiers a large number of data distributed both spatially and in time accross the area of interest. In a classical approach, dedicated floating cars are deployed to act as a mobile traffic sensors. Those should be equipped with special navigation and communication units, and privacy and security issues should be resolved before the implementation, usually by fi nding a group of mobile users who voluntarily provide their location data in order to yield other benefits. For instance, taxi drivers may be interested in providing their whereabouts in exchange for continuous monitoring and assistance in case of being attacked.
Mobile communications-based TIS resolves the obstacles of classical TIS by utilisation of the anonymous mobile user data, combined with GPS readings, where and when available. Every mobile user effectively become a floatin particle, sensing the traffic status of his/her surroundings. Naturally, not everyone can be considered travelling in a vehicle. Therefore, in the process of data preparation a fi ltering procedure is needed to extract only those particle data sets referring to mobile users involved in traffi c. This can be conducted by
monitoring the history of particle’s velocity, for instance. After selection of mobile users involved in traffic, the sets of velocity estimation data area used in traffi c status estimation for specifi ed road segments. The accuracy of the estimation depends on both particle’s velocity and positioning estimation. Processed data and traffi c status estimates for pre-selected road segments are stored in a database and available for provision within various information services (traffi c status on mobile devices, internet, traffic displays along the roads, travel time estimations etc.). An architecture supporting mobile network-based TIS is depicted on Fig 5.
Location-related data collected and stored within the core mobile communication network have been unexploited so far. Recent advancements provide means for exploitation of mobile user locationrelated data for location-based and ITS services, with preserved privacy of mobile users and without need for building separate ITS infrastructure. Improvement of the quality of service for the mobile network-based ITS through development of advanced algorithms and methods for traffic status estimation and system integration with GNSS/GPS-based systems will be issues for further development.
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