Attributes of direct measurement of inductance in a loop detector for traffic control

Inductive loop detectors for traffic control conventionally operate by sensing a resonant frequency shift when a vehicle passes over a loop. Using a digital system to measure the inductance as a function of time, better sensitivity and additional capability is available. This includes the ability to use both amplitude and frequency domain information to separate signals produced by vehicles that introduce only small interactions with the loop from signals due to vehicles in adjacent lanes. The detection scheme also permits an alternative approach for detecting bicycles and the option of placing detectors farther from an intersection to better control high speed traffic.