Abstract
In this paper, the author discussed the relation of magnetic sensor attached to the vehicle and various bar code patterns made of the ferrite mixtures and spaces by means of vehicle running test. This experiment yielded the following results: 1) The serial signal transferred from output of sensor by switching circuit represented the length of bar code set on the road. 2) The number of loop counted in the micro-processor was nearly proportional to the length of bar code independently of vehicle speed and of scale-down-pattern. 3) This bar code system functioned properly, even though with snow, ice and dust between sensor and the bar code and also functioned below the freezing point.
