Within automotive OEM's, there has been increasing reliance on vehicle system modeling for: Successful implementation of new system level technologies; Meeting the quality and efficiency demands of shorter product development cycles; and Enabling more analytical optimization of hardware and software systems. Ensuring high efficiency and quality of system engineering work reliant on vehicle system modeling requires enabling enterprise wide model sharing, highly coordinated cross-functional model development efforts and standard methods and processes. This paper discusses key elements and requirements of standard methods and processes for vehicle system modeling. First, obstacles to wider reliance on system modeling within current system engineering processes are described. Then a discussion is presented of model specifications as a central element in enabling more of a model driven vehicle system engineering process. Further, a model driven system engineering process is described that can be applied to the development of new vehicle system technologies. A key element of the process is the use of model specifications to drive system specifications.