ARC-IT: How the ITS Reference Architecture is Guiding the Future of Connected and Automated Vehicle Applications

Have you ever gotten into the heart of a project or system development and started experiencing the feeling of scope creep? That there are influences on the system that were not apparent at the start? Well, you are not alone. But fortunately, this situation can be avoided if an Intelligent Transportation Systems (ITS) architecture is developed as a reference framework to support the project planning and systems engineering processes reflecting the transportation community’s perspectives and needs.

An ITS architecture makes it possible to see other influences or impacts on your intelligent transportation system so you can anticipate and coordinate with those related systems and stakeholders before you start developing requirements. This has become even more important as the world of ITS has expanded with the advent of connected and automated vehicles (CAV). CAVs bring new stakeholders to the table, many of which have not traditionally been involved in transportation, making early interactions that much more important.

The birth of the National ITS Architecture

Developing an ITS architecture for a region, metropolitan area or ITS project does not start from a blank sheet of paper or an empty electronic document. It starts with content from a reference architecture that has defined the complex relationships of systems, stakeholders and transportation services based on years of evolving transportation technology, deployment and research.

In 1993, the United States Department of Transportation (USDOT) set out to define a functional framework to inform ITS standards development, planning and project implementation. The framework, known as the National ITS Architecture, was originally developed based on 29 ITS user services that provided visions for the various transportation services intelligent transportation systems would make possible.

As ITS technologies grew more capable, the services evolved and expanded, and the National ITS Architecture evolved with them. Iteris, under USDOT contract, has led and supported all aspects of the National ITS Architecture’s evolution from the beginning to what it is today. Figure 1 - Timeline illustrates the evolution of ARC-IT

The evolution of ARC-IT

The transportation environment is much different today than it was in 1993. Mobile communications capabilities have exploded and continue to expand. The wireless data services have become so capable that they support advanced ITS operations such as the enablement of connected and automated vehicles, and their related applications.

In 2012, Iteris led the development of the Connected Vehicle Reference Implementation Architecture (CVRIA), which shared the CAV-related ITS components of the National ITS Architecture. The CVRIA was developed to support USDOT CAV research and the Connected Vehicle Pilot Deployment Program that put connected vehicle technologies and services in three real-world settings. In 2017, the CVRIA was integrated with the National ITS Architecture to provide a unifying framework that covers all of ITS. The expanded reference framework became the Architecture Reference for Cooperative and Intelligent Transportation (ARC-IT) Version 8.0.

With the release of ARC-IT Version 8.0, any transportation organization could explore how connected and automated vehicle services could be integrated with traditional and/or intelligent transportation systems. ARC-IT was recently updated to Version 9.0 in November 2020 and the framework with new ITS and CAV services, drawing from growing involvement from domestic and international communities. Figure 2 - ARC-IT comprises four views to provide a framework for intelligent transportation systems.

Why ARC-IT matters to the industry

ARC-IT is not just a functional framework that applies to the United States. It is a model of the functionality, processes, data and information exchanges, and ITS standards that are needed to establish trusted communications between mobile devices and vehicles, as well as with the infrastructure, to improve transportation safety, mobility, efficiency, equity and sustainability. The reference helps to achieve this by:

• Setting a common language – ARC-IT content enables transportation stakeholders from all modes and jurisdictions to find a common language and platform around which to discuss their transportation needs and how to address them.
• Establishing mutually beneficial solutions – ARC-IT is a reference from which a tailored path to ITS and CAV solutions that meet the needs of a community can be defined so that all involved parties understand how the solutions fit together and what services and benefits they can provide.
• Guiding future applications – ARC-IT provides a foundation upon which ITS and CAV can be planned, developed and deployed.

Transportation technology, including connected and automated vehicles, is advancing quickly, making it hard to have the latest capabilities on any project or system for very long. In addition, any one CAV service can be implemented in many ways, resulting in multiple variants of technology application for the same service. This is not a bad thing, but it elevates the importance of a common reference architecture that defines the functionality and information exchanges, as well as pointing to the applicable standards, necessary to deliver a transportation service.

The functionality remains constant, while the technologies applied for service implementation range widely. This puts even more importance on planning ITS and CAV up front, and guiding project implementation from a stakeholder consensus approach around a common reference and ITS standards.

Preparing agencies for connected and automated vehicles

Iteris has developed, under the USDOT National ITS Architecture Program, training and support tools to make it possible for stakeholders to apply ARC-IT to their own environment for planning and project development.

We have assisted state, regional and local public agencies in the development of their regional ITS architectures based on ARC-IT, and have developed project architectures for agencies that reflect the portions of the regional ITS architecture that are implemented with the planned project’s development and deployment. This becomes even more important as agencies wade into CAV implementation.

Iteris provides the connected and automated vehicle experience as well as the ARC-IT knowledge to define regional and ITS project architectures for public agency clients.

Most recently, Iteris updated the Florida Statewide ITS Architecture and seven Regional ITS Architectures for the Florida Department of Transportation (FDOT). Stakeholders in each of these eight architectures are moving forward with CAV planning and implementation, including projects that will implement services for connected vehicle traffic signal systems, intersection safety warning and collision avoidance, and automated vehicle operations.

ARC-IT provides a basis for discussions with CAV-interested stakeholders to determine what is included in a CAV project to meet their needs. Using the ARC-IT physical and functional objects, services, information flows and ITS standards required to address CAV, Iteris has defined these architectures to address “what” needs to be developed and deployed.

An ITS architecture does not define the technology to be used, but the functions - the “what” - to be performed.

The resulting regional ITS architectures and ITS project architectures put stakeholders in the right place to explore the options they have available for deployment with the knowledge of the entire system environment, not just a particular component of it.

The Bottom Line

CAV holds much promise for safety and mobility improvements. With the proper framework defined in a regional ITS architecture that uses ARC-IT as a reference, the foundation is laid to explore the technologies that can be built on that framework and deliver the transportation services that meet a community’s needs, and advances safety, mobility and sustainability of the transportation system now and into the future.

Is your agency ready for connected and automated vehicles? Contact us to learn more about Iteris’ connected and automated vehicle solutions.