An intelligent transport system (ITS) reference architecture is a tool that describes how an ITS delivers one or more ITS services. It includes a high-level description of the major elements and the interconnections among them that are needed for the service(s) to be provided to stakeholders. It provides the framework around which the interfaces, specifications, and detailed ITS designs can be standardized within ITS standards.

By contrast, ITS standards are often focused on design details. While the development of these standards may be initiated by a single ITS user need, they are often (and properly) written in a generic format that allows for application in a broad array of contexts. However, this can present a challenge to the reader in understanding the original purpose of a standard and whether the standard is intended for other environments.

This document defines documentation rules for standards that define interfaces between or among system elements of an ITS reference architecture. This includes:

a) requirements for documenting aspects of the ITS reference architecture;

b) terminology to be used when documenting or referencing aspects of the ITS reference architecture.

In compiling this document, the authors have assumed that contemporary systems engineering practices are used. Such practices are not defined within this document.