Inductive Loop Technology

Inductive loops are a simple and reliable way to detect the movement of vehicles over a road surface.

As a vehicle approaches the loop, the metal in the car causes a disturbance in the magnetic field created by the loop and changes the loop's inductance. Inductance is proportional to the magnetic field and can be measured, creating a means by which speed and vehicle size can be gauged. Inductive loops are quite reliable but when certain variables like car size, weather or degradation of wires play their part the performance can drop.