Method for detecting traffic anomally of urban road with equidistant spatial-temporal division

Equidistant spatial-temporal division is used in the detection of a traffic anomaly. A spatial-temporal subzone is created by dividing one day into several time segments of 30 minutes, each defined as a time subzone; dividing one implemented area into several spatial segments of 200m x 200m, each defined as a spatial subzone; and defining an intersection of one time subzone and one spatial subzone as a spatial-temporal subzone. Historical and real-time GNSS positioning data of floating vehicles is respectively pre-processed into sampled historical and real-time vehicle speed data relating to historical and real-time trajectories. These are used in a finite mixed modelling method to establishing respective historical and real-time travel speed probability distributions. Jensen-Shannon divergence is then used to measure a difference between said historical and real-time travel speed probability distributions and an anomaly index of traffic conditions is determined from said difference. The accuracy of said anomaly index is then evaluated.