Abstract: For the different kinds of packet transmission requirements in vehicular ad-hoc network (VANET), this paper proposes a hybrid message transmission mechanism and routing algorithm combining vehicle to vehicle (V2V) and 5G cellular communications. The packets in VANETs are divided into two types: delay sensitive and delay insensitive. The delay-sensitive packets can be transmitted efficiently taking the advantages of 5G cellular network with low delay, high reliability and wide network coverage. Since the ad-hoc network has a lower cost than the 5G cellular network, a routing algorithm based on bus assistance is designed for delay insensitive data packets. In order to reduce the probability of communication link disconnection, a prediction mechanism for the update-time of the neighbor table is proposed. The effectiveness of the scheme is verified by a large number of simulation experiments. Simulation results show that the proposed routing scheme can improve the delivery ratio of packets, reduce the end-to-end delay and decrease end-to-end transmission hops.