抄録
This paper describes the development of the instrument which is used to detect the traffic of the car by the flux-gate magnetometer. The variation of the magnetic field intensity of the car is observed by using a flux-gate magnetometer which is set beside a road. It is found out that the variation of the magnetic field intensity of the large vehicles is bigger than the small vehicles by ten times. The variations of the magnetic field intensity of the vehicles (large vehicles and small vehicles ) are estimated with the computer-based simulation. Comparison with the car traffic measured by the automatic measurement, and the usual visual observation was done. It is almost the same is the total traffic though there are some differences in the traffic by the large vehicle and the small vehicle. The traffic can be precisely measured if threshold value is adjusted to the appropriate value.
