There are occasions when it is necessary to impose a particular form of behaviour, or a particular organisation structure, on integrated ITS. Examples include the need to:
- Localise safety functions so that they will continue to work when “higher” (non-safety) functions are absent;
- Provide a command and control structure that conforms to certain legal, or constitutional, requirements.
In these circumstances an overall concept has to be specified to which the system structure must conform (see below).