Evaluation of results of the SmartLIM (Laser Inferometric Magnetometer) as a traffic counter

A fiber optical magnetometer, SmartLIM (Laser Interferometric Magnetometer), has been developed. The SmartLIM adopts the Mach-Zehnder interferometer to detect the local disturbance of the geomagnetic field produced by a car driven nearby. Its high sensitivity enables us to install the detector at the a depth of 0.5m from under the road surface, or beneath the bottom side underside of an elevated road. . The SmartLIM was tested for over four seasons at under an elevated road after following our factory site test. The results have confirmed its excellent detection capability and usefulness as a traffic counter.