I. Introduction
Recent advances in vehicle-to-everything (V2X) network and 5G communication have allowed for data transmission with high reliability and low latency between connected and automated vehicles (CAVs), roadside facilities, and cloud servers. The notion of vehicle-road-cloud integration or cloud control has subsequently attracted extensive attention and promised transportation revolution [1], [2]. Typical research include multi-vehicle platoon control [3], [4], cooperation for multiple connected vehicles at unsignalized intersections [5], and urban traffic network management [6]. These research demonstrate the potential of vehicle-road-cloud integration in significantly reducing energy consumption and improving traffic efficiency [7].