Along with non-safety related applications, traffic safety is the major concern of the Vehicular Ad-hoc Networks (VANETs). However, the mobility management due to the high speed of vehicles, intermittent connectivity, and frequent topology variations are some of the crucial roadblocks. These challenges impose setback for quality of service (QoS) guarantee that leads to unfulfilled goals of VANETs deployment. The centralized control of the Software-Defined Networking (SDN) paradigm allows optimum utilization of global network view to meet the QoS requirements. Furthermore, by a systematic design of the SDN control plane, the issues of mobility management and poor network connectivity can also be addressed in an efficient manner. In this paper, we propose an SDN-based architecture that utilizes cloud computing and deals with inherent constraints of VANETs. A logically distributed control plane is devised for seamless connectivity, mobility management, and QoS support. The proposed model achieves optimum performance and robustness against failures by harnessing capabilities of SDN and cloud computing. We implemented the QoS and routing applications to evaluate the proposed model. The comparative experimental results are presented to demonstrate the effectiveness of the proposed framework.