The European Car-to-Car Communication Consortium in relation with the American Vehicle Safety Communication project has been playing a key role in the development of the concepts and technologies which are now at the origin of the standardization activities and research projects (PREVENT, SAFESPOT, CVIS) being introduced. Many safety applications (some of them being summarized here) will use this standard infrastructure for contributing to a safer road environment. Along the ISO OSI reference model the authors describe medium access control, routing in WAVE/DSRC (Dedicated Short Range Communications), 802.11p, and accompanying standards based on the communication architecture defined by the Car-to-Car Communication Consortium and the National Vehicle Infrastructure Integration Consortium (VIIC), as within the Federal ITS Program (RITA). Furthermore, this book introduces and describes future automotive applications such as cooperative driving utilizing such car-2-X (or vehicle-2-x) communication between vehicles and road infrastructure. Validation of these novel applications is a must before market introduction. Therefore this book introduces comprehensive simulation environment combining existing approaches for application, traffic and network simulation.