Sharing traffic information on the vehicular network can help in the implementation of intelligent traffic management, such as car accident warnings, road construction notices, and driver route changes to reduce traffic congestion earlier. In the future, in the case of autonomous driving, traffic information will be exchanged more frequently and more immediately. Once the exposed traffic incident is incorrect, the driving route will be misleading, and the driving response may be in danger. The blockchain ensures the correctness of data and tampers resistance in the consensus mechanism, which can solve such similar problems. This paper proposes a proof-of-event consensus concept applicable to vehicular networks rather than proof-of-work or proof-of-authority approaches. The traffic data are collected through the roadside units, and the passing vehicles will verify the correctness when receiving the event notification. In addition, a two-phase transaction on blockchain is introduced to send warning messages in appropriate regions and time periods. The simulation results show that the proposed mechanism can effectively feedback the correctness of traffic events and provide traceable events with trust verification.