Abstract
To prevent a car crash the system in which the car obtains its own positional information and exchanges it with the cars around it to control driving is effective. As the communication system to exchange the information various systems have been considered in the area of inter-vehicle communications and road-vehicle communications. But some problems for examples the delay caused by the time of establishing the communication link or a limit of the numbers of users still remain unsettled. In this paper the system specialized in positional and speed information that are most important information for safe driving is proposed. This proposed system uses M-sequence magnetic markers and variable frequency beacons and do not need the process of establishing the communication link. This proposed system is also effective in respect to that the number of vehicles whose positional and speed information can be obtained all at once is unlimited. The efficiency of this proposed system was showed by computer simulation and experimental results.
