I. Introduction
With the fast advancement of 5G, the VANETs and ITS technologies will play an increasingly important role in mitigating urban traffic congestion, and provide users with feature-rich services [1], [2]. In VANETs, vehicles are able to communicate each other, the communication massages are sent to trust authority (TA) to process for sharing and improving traffic safety which the traffic signals and traveling state of vehicles. In case of traffic emergency (traffic jam, vehicle collisions, etc.), the vehicles, road side units (RSUs) and TA are allowed to issue warning messages to inform nearby vehicles for avoiding traffic accidents.