Abstract
After the fruitful results of the IVHW project, the road safety actors are now gathering their efforts to strengthen the business model and the means of industrializing this successful technical system. To raise the interest of the first customers for this kind of equipment which begins to be efficient above a threshold of equipped vehicles of 15%, a solution is to manage to find some other applications to share the same radio link. Within the starting SAAV project the partners (Renault, PSA Peugeot Citroën, Cofiroute, Colas, LIVIC and Advanten) are trying to develop a radiocommunication system allowing several applications to coexist on the same 869.4-869.65MHz frequency band. This would allow to add maybe gate and/or doors command, crossroads and blackspots management to the hazard warning function. This crossroads and blackspots management would imply an enhanced role of the infrastructure in these special cases. The infrastructure could also be used to download some selected useful information to the driver. The challenge is to find the technical solution compatible with IVHW which would not blur the channel with non emergency messages and would still be low cost. The aim of IVHW project was to jointly develop and evaluate a system concept for an Inter-Vehicle Hazard Warning system giving precedence to European highway traffic taking into account costs and effectiveness. The IVHW system allows to warn drivers in due time if a potentially dangerous traffic situation occurs down the road. Thus, the system creates early danger awareness and enables the driver to adapt his driving behaviour accordingly. The technical concept is based on a radio broadcast from a vehicle in which the driver spots a danger or which is itself in a hazardous situation to some receiving vehicles. The warning message sent includes various attributes specifying its situation (last GPS locations, speed, course, ) and eventually the type of hazard encountered, that allows the receivers to characterise the danger according to their own situation. This assessment is achieved by the receiving vehicle through various filtering techniques. The technical solution proposed by SAAV for an enhanced and easier to launch IVHW could include the FDMA use of some other channels of the 869.4-869.65MHz band or the use of some GPS time managed TDMA. In both cases, the principle would be based on dividing the radio traffic between an emergency and control channel and several traffic channels.