The control structures used in this analysis have a common format that stems from similar architectures of the three features. As has been previously mentioned, each feature is a cyber-physical system in which multiple hardware components are managed by an embedded controller. From a functional standpoint, the common architecture has three basic hierarchical levels: the human driver, the software module, and the physical vehicle with its subsystems. The same driver-software-vehicle system can be represented in much greater detail with many more levels of hierarchy, though for a high level analysis this level of abstraction is appropriate. In a safety guided design effort, each of the functional blocks and their links may be expanded to greater detail as design spaces are narrowed and implementation decisions made. Figure 4 below gives a template for the control structures that are a part of this analysis.