CHORUS - car horns used as sirens

In Germany, an extensive siren system was used in the past to warn the population against disasters: in case of natural hazards, industrial accidents or other disaster scenarios, situation centres could trigger the loud siren alarm. Detailed information about the danger situation was provided by radio and television. However, after the end of the Cold War, most sirens were dismantled in the mid-nineties. Today there exists a satellite-based warning system SatWaS, which distributes warning messages via radio and television. But if TV and radio are off, the warning goes unheard. A reinstallation of the former siren system would cost several hundred million Euros plus additional millions per year for maintenance. This is why German federal and state governments since years are searching for alternative solutions. Cell-broadcast systems can send mass SMS messages to mobile phones. Smoke detectors, radio-controlled clocks and weather stations with radio receiver can also trigger alarm. Despite the high distribution rate of some of these devices, it cannot be ensured that a warning reaches the entire population. Only individual persons or households can be warned, and only if the devices are on standby 24/7/365. The Fraunhofer INT develops a new warning system based on the use of car horns. In case of disaster the situation centres can define a region inside which every parked car will start to honk its horn corresponding to a predefined warning signal. To activate the cars they have to be equipped with a radio receiver, based on e.g. RDS, eWarn, GSM or different technology. The system will exploit the data of a GPS receiver coming with the introduction of the Telematics platform eCall. Besides sirens this system is the only one based on broadcast signals. It is independent from power lines and allows the free definition of alarm zones.