I. Introduction
Nowadays with the fast progress of artificial intelligence (AI) technology and the increase of high-quality trajectory data, it becomes feasible to build an accurate model to predict the vehicle speed [1], [2], [3]. The core task of vehicle speed prediction is to mine and explore collected vehicle trajectory data, extract temporal and spatial correlation features between surrounding vehicles, and predict the vehicle lateral speed and longitudinal speed in the future [4], [5]. Moreover, the accurate prediction results can further help the autonomous vehicle to make reasonable decision planning and enhance traffic safety and driving comfort in a complex traffic environment [6], [7], [8].