There may be several stages of prototyping. On this web-site, the focus is on Software Prototyping (also referred to as "simulation"), building a model in enough detail to validate significant portions of our design.
Test and Evaluation (T&E)
T&E is critical throughout system life. It is common for an independent integration-and-test team to exercise the system, as integration proceeds, to confirm that it meets requirements. Developers design systems based on their interpretation of requirements, but those interpretations will not always match those of the test team.
Keeping the Software Prototype Current
A software prototype is useful in concept validation and in early system development. When kept current, reflecting the actual deployed system, it can be useful to verify proposed upgrades. Repeating T&E processes including regression testing is integral to that process. It is also important to assure that documentation is kept current.
Early production versions will include limited numbers of operational components. As these proceed through alpha and beta testing, those numbers will increase.
The primary role of Software Prototyping in this early (conceptual) stage of CAV-System development is proof of concept.
The elephant - not currently in the room - is that we will not, here and now, create a real, live, operational system. With apologies to his disciples, Davius concedes that the resources are not yet at hand to accomplish this worthy goal. He counsels patience and perseverance.