The road surface temperature sensor consists internally of a thermopile and a thermistor. All objects continuously emit infrared radiation energy into the surrounding space. By measuring the infrared energy radiated by the object itself, its surface temperature can be accurately determined — this is the principle of non-contact infrared temperature measurement. The greatest advantage of an infrared thermometer is that it can calculate the surface temperature of an object by measuring the intensity of infrared radiation emitted by the target without making contact with it.