The state of Berlin awarded a consortium comprising DaimlerChrysler Services AG and Siemens AG a contract at the end of 1999 to set up and operate a traffic management centre called VerkehrsManagementZentrale (VMZ) Berlin. In April 2001, the two partners founded the joint operating company, VMZ Berlin Betreibergesellschaft mbH. This joint venture will operate VMZ Berlin over a period of 10 years. VMZ was set up as a public-private partnership with the investment costs for hardware and software covered by the Berlin government. After 10 years of operation the system will be owned by the Berlin government. It will depend on the creativity of the consortium and market response as to which services will be available for a fee only. It is not intended that the traffic management centre will take an active role in controlling traffic by traffic lights or motorway control. The traffic management centre will gather data which will be used for the future Berlin traffic control centre. Traffic control authorities will have access to comprehensive maps of the current traffic situation and traffic forecast which can be used for decisions on traffic control. As one of the core functions the current traffic situation is estimated by collecting current traffic volume and speed at about 180 urban and 200 motorway detection sites and utilizing this information in a strategic traffic model with roughly 8000 links. Real-time route choice estimation is based on the Path Flow Estimator by Bell supported by an offline analysis of historical detector data to calibrate origin-destination matrices as good starting solutions. In time-steps of five minutes real-time link volumes are estimated by a propagation algorithm in which the estimated route choice is used to distribute detector values all over the road network. Precise origin-destination tables are crucial to generate estimated link volumes and speeds within a given quality. The paper presents the propagation algorithm in detail. A quality index has been computed by omitting single detectors while estimating link flow and speed and comparing estimated and counted values thereafter. The quality index considers level of service by using estimated volume and link capacity as input. The accuracy of estimated and observed level of service is within a 90%-range. For the covering abstract see ITRD E126595.
Abstract