Road congestion monitoring method based on idling sound frequency spectrums of automobiles

The invention discloses a road congestion monitoring method based on idling sound frequency spectrums of automobiles, which is characterized in that the method is based on the principle that idling sound of automotive vehicles accounts for a higher proportion in the environment in case of a traffic jam. FFT conversion for road sound collected within a certain time is performed, the frequency domain energy spectrums within the low frequency range (20 Hz-40 Hz) under the states of traffic jam and unimpeded traffic are obviously distinguished, and an obvious peak exists at the idling frequency in case of the traffic jam; and the steeping degree of the peak is converted into a factor k through an algorithm, and a road condition judgment standard corresponding to the k value is built. Experiments show that the road congestion can be effectively detected through the calculation of the k value.