In a near future, vehicles will be equipped with WAVE-compliant communication technology, enabling not only safety message exchange, but also infotainment and Internet access. However, without complete market penetration, other technologies must still be used, such as IEEE 802.11g/n to connect to public Wi-Fi hotspots in the city, or even 3G and 4G cellular networks. Due to the high mobility of nodes in Vehicular Ad-hoc NETworks (VANETs), the connectivity time between nodes becomes very short; therefore, it is essential to ensure the lowest handover time when moving between Road Side Units (RSUs) and other vehicles. In this paper, we implemented a multi-technology seamless handover mechanism for vehicular networks that integrates extended mobility protocols based on MIPv6 and PMIPv6, with a mobility manager that provides seamless communication between vehicles and the infrastructure, electing the best technology to maintain the vehicle connected without breaking any active sessions. To validate and evaluate the proposed handover approaches, a real-world vehicular testbed was setup, combining three technologies: IEEE 802.11p, IEEE 802.11g and 3G; handover metrics were obtained for all the combinations of these technologies. The results show that, if IEEE 802.11p is used in both vehicles and RSUs, the proposed approach is able to perform seamless handover with very low delay and no packet loss. The same conclusions apply for handovers between different technologies.