| 摘要 |
PURPOSE:To measure the traveling speed of a vehicle correctly with good accuracy by detecting the belt-like magnetic materials provided on or under the road surface so as to intersect orthogonally with the road by means of magnetic sensors on the vehicle. CONSTITUTION:Belt-like magnetic materials 2 are provided on the surface of a road 1 so as to intersect orthogonally with the road 1. Here, the materials 2 are produced by solidifying powder consisting essentially of magnetite (Fe3O4) with asphalt, a resin or cement so as to contain at least >=30wt% magnetite. Therefore, when an automobile 3 having 2 pieces of magnetic sensors 4, 5 passes over the material 2, the passage is first detected with the sensor 4 then an output is obtained in the sensor 5, and these outputs are put into an arithmetic circuit, whereby the accurate traveling speed is obtained instantaneously. |
