Method for detecting traffic anomaly of urban road

A method for detecting a traffic anomaly of an urban road. By using a vehicle-mounted GNSS positioning device of a floating vehicle, spatial position information on different time points is obtained; and by means of the analysis and excavation of a great quantity of track information of the floating vehicle, a traffic anomaly event of an urban road can be smartly detected. In the detection method, a traffic state is indicated by using the probability distribution of speeds in travels, a traffic state difference is reflected by using probability distribution difference measurement indictors, the principle is clear, the implementation is simple and convenient, and the detection rate is high.