Automatic speed limiting apparatus applied to highway hazy road

The invention provides an automatic speed limiting apparatus applied to a highway hazy road. The apparatus comprises a single-chip microcomputer, a dust sensor, a display, a speed detection module, a DC motor driving module and a DC motor. The dust sensor is used for acquiring physical signals related to a haze and transmitting electric signals which are corresponding to the physical signals and represent the haze to the single-chip microcomputer; the speed detection module is used for detecting the rotating speed of the DC motor driving a vehicle and sending the detected rotating speed to the display; the single-chip microcomputer, according to the electric signals representing the haze, determines the concentration of the haze, and controls the DC motor driving module according to the determined haze concentration; and the display is used for displaying the rotating speed detected by the speed detection module and realistically displaying the haze concentration determined by the single-chip microcomputer according to the signals related to the haze.