SOTIS - A self-organizing traffic information system

Traffic and Travel Information (TTI) systems in use today are based on a centralized structure. Sensors along the roadside monitor traffic density and transmit the results to a central unit where a situation analysis of the global traffic scenario is performed. The resulting traffic information is made available to the drivers via broadcast service or alternatively on demand via cellular phone. Within the FleetNet(1) project, a completely different proposal to establish a powerful traffic information system is developed and analyzed, which is based on Inter-Vehicle Communication (IVC). All vehicles are part of a Self-Organizing Traffic Information System (SOTIS): Each vehicle monitors the locally observed traffic situation by recurrently receiving data packets with detailed information from other vehicles. A traffic situation analysis is performed in each individual vehicle and the result is transferred via wireless data-link to all surrounding vehicles in the local neighborhood. No sensors along the highways, no central units and no broadcast stations or cellular networks are needed, which minimizes infrastructure costs. The complete system can be easily deployed and service charges for the end user can be avoided completely. Simulation results demonstrate that the proposed SOTIS technique can easily provide detailed information for each vehicle with an individual information range of more than 50 kin from the current position with high accuracy and low delay. Even in situations where only a small fraction of all vehicles (e.g. 2%) is equipped with the SOTIS technology, the full functionality of a traffic information system is available.