The SDN strategy optimizes the entire VANET efficiency by significantly controlling the traffic flow of the vehicular system. The SDN models separate the control and data plane in a systematic and programmable way, and they easily handle the abundant node density of the vehicular system. It assists the VANETs in effectively managing secure data transmission throughout the entire network. In SDN based VANET system, the data plane comprises the traffic forwarding devices, and the control plane manages the traffic flow of the whole communication system. The SDN-based VANET models permit the network to the network as dynamic, and it effectively handles the network resources in a cost-efficient manner. The main advantages of SDN-based VANET architecture are programmability, flexibility, centralized controlling ability, and resource handling.