Abstract
As one of the typical tasks of spatial temporal forecasting, traffic prediction has attracted extensive research attention in recent studies. Recent works usually combine time series modeling methods and graph neural networks to capture the temporal dynamic trends and spatial static dependencies together. However, we find that the temporal static characteristic and spatial dynamic correlations do also exist in the traffic flow, which are neglected or partially considered in previous methods. To capture such characteristics, we propose a novel method for traffic prediction, which models the Spatial Temporal Staticity and Dynamicity (STSD) together. Specifically, besides the traditional spatial and temporal encoder, we propose a pre-training module based on self-supervised contrastive learning to learn the location representation and thus capture the temporal static characteristic. Then, we propose a flow-aware dynamic graph learning module to capture the spatial dynamic correlations. Besides, to correct the original graph built from node distance, a feature reconstruction-based static graph learning module is introduced. The original, static, and dynamic graph are combined together in STSD to model the spatial staticity and dynamicity. Extensive experimental results on real-world datasets reveal that STSD can outperform existing traffic forecasting methods.