Components of Regional ITS Architecture

Regional ITS architectures have been developed in all 50 states and in every major metropolitan area over the past 2 decades. Many are now being updated and maintained by state and local agencies. They all tend to have similar components. Including each of the components provide complete coverage for the requirements of the Regulation and, in some cases, go beyond the letter of the regulation to ensure best practice and to support integration within the region.


Title: Regional ITS Architecture Components - Description: Figure showing all the components of a regional ITS architecture and how they are related to each other. Scope (at the top) defines the structure for what's included in all the components below. Stakeholders will relate to Inventory, User Needs, Agreements, and Roles & Responsibilities. Inventory will lead to Functions/Requirements, Services, and Interfaces. Functions/Requirements will lead to interfaces along with Services. User Needs will lead to Services along with Inventory. Services will lead to Roles and Responsibilities. Planning Objectives or Strategies will lead to Services. Interfaces will lead to Standards. Finally all the components will be defined in a set of Projects.

Regional ITS Architecture Components


The components that make up an architecture include:

-         Architecture Scope

-         List of Stakeholders

-         Connection of architecture to Regional Planning Goals, Objectives, and Strategies

-         Inventory of ITS Elements

-         Regional ITS Services

-         User Needs

-         Operational Concept (Stakeholders' Roles and Responsibilities)

-         System Functions and Requirements

-         System Interfaces Supporting the Services

-         Communications and Device Standards

-         Interagency Agreements to support ITS services and projects

-         Sequence of Regional ITS Projects


As shown in the figure above the scope of the architecture defines what will be included in each of the other components. Each of the components is connected to other parts of the architecture. Stakeholders are related to the Inventory, Agreements, and the Roles and Responsibilities. Inventory is connected to Functions/Requirements, Services/User Needs, and Interfaces. Functions are also related to Services and Interfaces. Services are also related to Roles and Responsibilities and Interfaces as well as Planning Objects/Strategies. Interfaces are also related to Standards. Projects are at the bottom to indicate that each component is implemented in a project.


The National ITS Architecture or the "Architecture Reference for Cooperative and Intelligent Transportation" (ARC-IT) is used as a template to create regional ITS architectures that are tailored for a specific state, metropolitan area, or other region of interest (e.g., a major corridor or a National Park). ARC-IT provides the fundamental building blocks: the physical objects, interfaces, service packages, user needs, and functions that are selectively included in the regional ITS architecture and customized as necessary to fully reflect the envisioned regional transportation system.


The regional ITS architecture defines the links between the pieces of the system and the information that is exchanged on each connection, and the ITS standards that can be used to support those connections. Over 300 regional ITS architectures have been developed so chances are good that you already have one in your region.


The approach for updating (if you already have a regional ITS architecture that has been created or updated in the not too distant past) or developing (if your region does not have an ITS architecture, or it was originally developed so long ago that you are essentially starting from scratch) is described at Regional Architecture Update/ Development Approach.


Once a Regional ITS Architecture has been created (or updated), it needs to be updated from time to time in order to capture the current plan for development of ITS in a region. A discussion of why an architecture needs to be updated as well as consideration of what should be updated and who should be involved in the update is described in Regional ITS Architecture Maintenance.


RAD-IT iconA key tool in updating or developing regional ITS architectures is the Regional Architecture Development for Intelligent Transportation (RAD-IT) software tool, which allows regions to customize ARC-IT for a specific region. Each of the component descriptions above includes a discussion about how that component is expressed in RAD-IT. For more information about RAD-IT see the Resources/Tools page on the website.