With the increasing demand for quality of service (QoS) by end-users, mobility management, IP flow mobility and data offload are key features needed in next-generation wireless networks. With the wide deployment of WiFi (e.g., home, vehicle, smartphones, laptops) and onboard unit (OBU) in automotive and public transportation systems (PTS), it is important to provide mechanisms that allows data offload and seamless handover of sessions between cellular-based vehicular networks (3G/4G) and WiFi as well as IP flow mobility for users in automotive and PTS. Such mechanisms will allow a better resource usage for network operators and guarantee higher QoS for users while considering value-added services in vehicular communication networks (VCNs). Although, several approaches have been proposed for mobility management such as Mobile IP (MIPv4 and MIPv6) and Network Mobility (NEMO), seamless mobility and efficient flow mobility are not guaranteed. This paper proposes a new mechanism for selective IP traffic offload (SIPTO) for VCNs. The proposed solution has been prototyped and the performance evaluation shows improvement in terms of throughput, energy consumption, and flow mobility latency when compared to existing mobility management approaches.