Traffic Control Magnetic Loops Electric Characteristics Variation Due to the Passage of Vehicles Over Them

From previous studies, mathematical models of magnetic fields generated by different kinds of magnetic loops are known, as well as the high correlation between those models and the real values. On this occasion, we intend to determine the effect on the buried magnetic loop response when vehicles pass over them. Specifically, a theoretical model that reflects the values of the magnetic induction in the loop is presented, as well as the changes it undergoes due to mutual induction phenomena occurring between the loop and the vehicle, when the latter passes over the former. The theoretical values are compared with the actual measurements and the accuracy of the model is checked. Besides, we present a new oscillator circuit; a component being the loop. This circuit has outstanding advantages in comparison with the currently existing ones. Finally, this induction change is used to cause the oscillation frequency modification of a resonant circuit, which in turn is one of the changes used for vehicles detection, identification, and classification. A program is designed and used to obtain the magnetic profile of several vehicles when passing over a rectangular loop.