Inductive loops are considered the most reliable traffic classification detection method available.

An inductive loop consists of wire "coiled" to form a loop that usually is a square, circle or rectangle shape that is installed into or under the surface of the roadway.

Inductive loops work like a metal detector as they measure the change in the field when objects pass over them. Once a vehicle drives over a loop sensor the loop field changes which allows the detection device to detect the presence of an object (mainly a vehicle). Inductive loops are referred to as presence detectors and in traffic detection are often used in combination with axle sensors to collect classification data such as speed and length data.

Learn more about inductive loops.