A traffic state prediction method based on spatial-temporal data mining of floating car data by using autoformer architecture

Floating car data (FCD), characterized by wide spatiotemporal coverage, low collection cost, and immunity to adverse weather conditions, are one of the key approaches for intelligent transportation systems to obtain real-time urban road network traffic information. The research aims to utilize GPS data from taxis in Shanghai and vector geographic information data of the road network, with urban expressways as the research focus. Based on the different driving characteristics of expressways and the vehicles on the ramps below, a clustering analysis is employed to determine all floating vehicles traveling on the target road. Furthermore, an adaptive buffer zone consistent with the road orientation is established based on road vector geographic data. This allows for the extraction of FCD within segmented areas, and the average vehicle speed for that road segment is obtained through weighted calculations. This method fully exploits the natural characteristics of taxis in urban areas with a wide spatiotemporal distribution. The data effectiveness and coverage reach 90.2% and 85.7%, respectively, significantly surpassing the traditional grid-based extraction method for FCD. Additionally, to capture the long-term spatiotemporal dependencies of road network traffic states, a spatial-temporal autoformer (STAF) network based on spatial-temporal sequence autocorrelation is employed for traffic state prediction. The results indicate that the STAF method demonstrates good performance in medium- and long-term prediction. We believe that the proposed FCD mining method in this paper provides a new approach for efficiently extracting large-scale road network traffic states and conducting medium- to long-term predictions.