Architecture Reference for Cooperative and Intelligent Transportation

The communications view The physical view The functional view The enterprise view

ARC-IT includes all views of the National ITS Reference Architecture - Enterprise, Functional, Physical and Communications views; as well as over 150 service packages that present slices of the architecture to show how ITS could be deployed to solve real transportation needs. Version 9.2 focuses on improvements that support Multimodal Accessible Travel (MAT), the Management of Electronic Traffic Regulations (METR) and other new concepts and refinements. Read more...


November 2023 - The ARC-IT website is updated with enhancements and bug fixes to the RAD-IT & SET-IT software. See below for details.


RAD-IT 9.2.1 includes new document output settings, a new Services Readiness output report, and corrects known performance issues while supporting conversion from previous versions. Read more...


SET-IT 9.2.1 includes enhancements to the search feature, fixes to the document generator, and fixes for occasional crashes, along with other fixes for known issues and to support conversion from previous versions. Read more...




The Architecture Reference for Cooperative and Intelligent Transportation (ARC-IT) provides a common framework for planning, defining, and integrating intelligent transportation systems. It is a mature product that reflects the contributions of a broad cross-section of the ITS community (transportation practitioners, systems engineers, system developers, technology specialists, consultants, etc.).

ARC-IT is a reference architecture: it provides common basis for planners and engineers with differing concerns to conceive, design and implement systems using a common language as a basis for delivering ITS, but does not mandate any particular implementation. ARC-IT includes artifacts that answer concerns relevant to a large variety of stakeholders, and provides tools intended for transportation planners, regional architects and systems engineers to conceive of and develop regional architectures, and scope and develop projects.

To get started, begin with the menu bar above:

  • Architecture contains links to all of the content inside the architecture, and describes the structure of the architecture. In particular:
    • Service Packages represent slices of the architecture that address a specific service like traffic signal control and provide the most straightforward entry into ARC-IT content.
    • Views and its sub-menus provide view-specific content; if for example you are looking for a particular information flow, or a particular communications profile, browse the relevant physical and communications sections here.
    • Methodology and its sub-menus describe the structure of the architecture: how it is built, how the artifacts within are inter-related.
    • The Security section describes how security is addressed throughout the architecture and provides links to cross-cutting security content.
  • Architecture Use describes how to use ARC-IT, from the perspective of a regional architect, transportation planner or project systems engineer.
  • Architecture Resources provides access to all ARC-IT content in user-downloadable forms. Notably this also includes access to our tools: RAD-IT and SET-IT, that provide you with means to manipulate the architecture according to models' rules, customizing the reference architecture to your regional or project needs.
  • Architecture Terminology provides those definitions that permeate these pages.
  • Contact the Architecture Team gives you a direct line to the source. We want to hear from you! If you have questions, concerns or find an error (say it isn't so!) we'd like to know about it!