The European Union funded projects DRiVE (Dynamic Radio for IP Services in Vehicular Environments) and OverDRiVE (Spectrum Efficient Uniand Multicast Over Dynamic Radio Networks In Vehicular Environments) aim at enabling spectrumefficient high-quality wireless IP communication in a heterogeneous multi-radio environment to deliver invehicle multimedia services. The IPv6 based network architecture for IP over multi-radio access networks and traffic control aspects has been developed in the DRiVE project (cf. [1] and [2]). This paper presents relevant results of a performance analysis by simulation of the TCP handover behavior in the DRiVE multi-radio environment. Furthermore, the OverDRiVE project extends the scenario to mobile networks in larger vehicles like busses or trains, which imposes further interesting challenges on the IP-based network infrastructure and their protocols. The TCP handover evaluation will be continued in both the DRiVE and OverDRiVE scenarios.