The Functional Viewpoint addresses the analysis of abstract functional elements and their logical interactions rather than engineering concerns of how functions are implemented, where they are allocated, how they transfer information, which protocols are used, and what method is used to implement them.

The Functional Viewpoint of HARTS focuses on the behavior, structure, and interaction of the functions performed within the C-ITS environment.

The behavior of a Function (aka Process) is the set of actions performed by this element to achieve an objective. A Process performs actions to achieve an application objective or to support actions of another Process. This may involve data collection, data transformation, data generation, data generation or processing in performing those actions. Functional Views define Processes to control and manage system behavior, such as monitoring, and other active control elements that are part of describing the functional behavior of the system. They also describe data processing functions, data stores and the logical flows of information among these elements.

The Functional Viewpoint heritage from the CVRIA and US National ITS Architecture is modeled using a Structure Analysis methodology, based on the work of Hatley/Pirbhai. The Functional content imported from the FRAME architecture follows a similar methodology, which enables linkage between the architectures. Since functional artifacts in CVRIA can be related to Physical artifacts, we can transitively associate FRAME funtional artifacts with HARTS physical artifacts as well.