Abstract: A system for monitoring ferromagnetic materials in proximity to a sensing region, which is particularly applicable to traffic monitoring and controlling. A magnetic probe generates a signal in response to magnetic flux changes caused by a vehicle moving through a sensing area. A processor analyzes the signal to determine the duration of the signal and correlates that duration to a vehicle velocity. A checking system periodically sends a checking signal to the magnetic probe and monitors the return signal to verify that the probe is operative and also analyzes the return signal to determine whether a stationary vehicles is in the sensing area.