In-vehicle embedded computer control systems are special cases of a distributed real-time system. In the design step these systems should be validated and optimised. As the part of the Franco-Chinese program PRA SI99-04, we presented during a seminar in Wuhan University of Technology (China) our research results on the validation techniques allowing us to verify the real-time constraints meeting of such systems. These techniques include modelling and performance evaluation based on modular simulation model building process and tool, schedulability analysis of periodic tasks and messages, combined stochastic and deterministic analysis of the system's robustness faced to transmission errors and dual-priority dynamic scheduling of periodic and non periodic messages. They are applied first to a single CAN networked system and then to a multiple networked system (CAN and VAN). The PRA SI99-04 project aiming to integrate security control (car colliding and fire extinction) to the existing embedded system in a car is outlined. Other related research activities developed in PREDIT-CAROSSE project (LORIA-PSA-LIP6) and in AEE ("Architecture Electronique Embarquée") national project are brief described.