Guaranteed selected quality of telecommunication service and wide area coverage are typical requirements of the ITS (Intelligent Transport Systems) applications. Extensive range of wireless data services with reasonable coverage is provided by public wireless services operators, however, mostly no guaranteed relevant range of quality and security is available. ITS services require cost-effectively solution which can be resolved by combination of the “core” public solution with the other public as well as private services where and when it is needed. Such approach requires implementation of the relevant flexible system architecture supported by the efficient decision processes. ITS specific service security requirements would not underestimated, as well. Special situation is identified in case of the C2I (Car to Infrastructure) and C2C (Car to Car) communication namely if the vehicle on board unit is interconnected with the vehicle CAN (Controlled Area Network) based network. Such configurations significantly increase potential of dangerous intruders´ attacks. Probability of the critical hazards appearances grows if the ITS data are accessible in the wide area networks. That is also the main reason why relevant telecommunications security support is understood as one of the crucial part of the ITS telecommunications solution.