Heavy traffic including congestion can be observed on urban roads all over the world. In view of limited space for new roads, it is necessary to improve the exploitation of the existing network. In order to solve this problem the number of telematics applications increased rapidly over the last couple of years. This development was mainly pushed by new wireless communication and location sensing technology. Consequently, traffic management and mobility services providing online travel information for road users were established over the last years. Traffic information is usually broadcast via radio or TV as well as via modern channels like the internet or cellular phone networks. Conventional data sources for traffic information are based on traffic volume measurements by inductive loops or infrared sensors. The major problem of this approach is the reconstruction of travel time and the routes of the vehicles in the road network. A more reliable method for analyzing the travel time and routes of vehicles on urban roads is described. The approach is based on floating car data (FCD) using the global positioning system (GPS). Nowadays an increasing number of commercial vehicles are equipped with GPS devices. In this context, a project was established with a Berlin taxi company. 300 Taxis equipped with a GPS receiver and a wireless communication device act as FCD data supplier. At one-minute intervals each taxi sends its current position to the taxi headquarters, where the data are processed for the online taxi client disposition. Using synergies from the taxi disposition at our institute, a real-time FCD traffic information system was developed. In May 2001 the real time operation of the FCD system was started, exploiting the GPS data of the taxi disposition software. Since May 2001 several million position data have been collected from the taxi fleet. These data are an excellent basis for data mining analyzing the daily variation of travel time on almost all the major roads of Berlin. The travel times on different types of roads are compared and the reasons for fluctuation patterns are discussed. The general traffic demand, weather condition, seasonal effects, events and road works all influence traffic flow. With this input it is possible to generate travel time maps for the Berlin road network. The results of our research are the basis for real-time traffic monitoring and management as well as for real-time travel time forecast in urban networks. Furthermore, the analyses are used for fleet management of a Berlin waste disposal company. The routing algorithms are implemented for the optimization of routes of the vehicles as well as for the reduction of fuel consumption. For the covering abstract see ITRD E124693.
Abstract