An integral component of the National ITS Architecture analysis, the institutional layer represents the existing and emerging institutional constraints and arrangements that are the context for all ITS deployments. The transportation layer and communications layer together provide the technical framework within which interoperable systems may be implemented. The institutional layer introduces the policies, funding incentives, working arrangements, and jurisdictional structure that support the technical layers of the architecture. This institutional layer provides the basis for understanding who the stakeholders will be and the roles these implementers could take in implementing architecture-based ITS systems.

The system defined as the electronics, communications or information processing used singly or integrated to improve the efficiency or safety of surface transportation.

See architecture interconnect.

See system inventory.

Defines an architecture of interrelated systems that work together to deliver transportation services. An ITS architecture defines how systems functionally operate and the interconnection of information exchanges that must take place between these systems to accomplish transportation services.

Any project that in whole or in part funds the acquisition of technologies or systems of technologies that provide or significantly contribute to the provision of one or more ITS user services.

Areas of ITS which can be used to enhance surface transportation security. The National ITS Architecture provides entities (subsystems and terminators), functions, and interfaces that cover aspects of the eight ITS security areas.

The office of the United States Department of Transportation (USDOT) established to oversee and guide the multi-modal National ITS program.

Existing transportation systems, communications systems, and institutional processes.

A term used when denoting a progression through a series or sequence of differing stages of development.

The logical architecture view of the National ITS Architecture defines what has to be done to support the ITS user services. It defines the processes that perform ITS functions and the information or data flows that are shared between these processes. The logical architecture was developed using Structured Analysis techniques and consists of data flow diagrams, process specifications, and data dictionary entries. The logical architecture has also been called an "Essential Model" because it is not technology specific, nor does it dictate a particular implementation. This implementation independence makes the logical architecture accommodating to innovation, scalable from small scale implementations to large regional systems, and supportive of widely varied system designs.

The Logical Architecture document contains three volumes: Description (Volume 1), Process Specifications (Volume 2), and Data Dictionary (Volume 3). These documents present a functional view of the ITS user services, contain diagrams that show processes and data flows among them, and define data elements, respectively.

Any ITS project that implements part of a regional ITS initiative that is multi-jurisdictional, multi-modal, or otherwise affects regional integration of ITS systems.

The market packages provide an accessible, service-oriented perspective to the National ITS Architecture. They are tailored to fit, separately or in combination, real world transportation problems and needs. Market packages collect together one or more equipment packages that must work together to deliver a given transportation service and the architecture flows that connect them and other important external systems. In other words, they identify the pieces of the physical architecture that are required to implement a particular transportation service.

The Market Packages document expands upon the market package discussion in the Implementation Strategy document by providing a comprehensive review of each of the market packages describing how market packages can be used to plan and implement integrated transportation systems customized to local needs. This document includes a number of examples that illustrate ways market packages can be applied in Regional ITS Architecture and Project ITS Architecture development activities. Through these definitions, analyses, and examples, the Market Packages document provides a comprehensive review of the market packages and how they can be used to plan and implement integrated transportation systems customized to local needs.

The forum for cooperative decision making for the metropolitan planning area.

The first of the technical documents, the Mission Definition document covers a broad range of ITS related issues. It contains the overall mission of ITS deployment, as well as the operational concept, which deals with specific ITS goals and objectives; ITS user groups and other stakeholders; ITS user services; and potential sources for funding, operations and maintenance. The document also defines operational requirements at the system level, user requirements, performance requirements, and program requirements. These concepts are important aspects of the National ITS Architecture since they provide the overall direction for the ITS program.

A common, established framework for developing integrated transportation systems. The National ITS Architecture is comprised of the logical architecture and the physical architecture, which satisfy a defined set of user service requirements. The National ITS Architecture is maintained by the United States Department of Transportation (USDOT).

Jointly developed by US DOT and ITS America with substantial involvement from the broader ITS community. The purpose of the National Program Plan was to guide the development and deployment of ITS. It defined the first 29 user services and their corresponding user service requirements.

This document assesses the technical performance of the National ITS Architecture on a number of system-level and operational-level criteria. It could be helpful in supporting the case for ITS deployment, as it provides a measure of the degree to which ITS can help achieve some regional transportation goals.

The physical architecture is the part of the National ITS Architecture that provides agencies with a physical representation (though not a detailed design) of the important ITS interfaces and major system components. It provides a high-level structure around the processes and data flows defined in the logical architecture. The principal elements in the physical architecture are the subsystems and architecture flows that connect these subsystems and terminators into an overall structure. The physical architecture takes the processes identified in the logical architecture and assigns them to subsystems. In addition, the data flows (also from the logical architecture) are grouped together into architecture flows. These architecture flows and their communication requirements define the interfaces required between subsystems, which form the basis for much of the ongoing standards work in the ITS program.

The Physical Architecture document describes the transportation and communications layers resulting from the partitioning of the processes within the logical architecture, presents architecture flow diagrams that show data passing among physical subsystems, and provides characteristics and constraints on the data flows.

Entities are the persons, places, and things that make up an intelligent transportation system. In the physical architecture, an entity represents a National ITS Architecture subsystem or terminator.

A function or activity identified in the logical architecture view of the National ITS Architecture that is required to support the ITS user service requirements. The logical architecture presents processes in a top-down fashion beginning with general processes (e.g., "Manage Traffic") that are then decomposed into more detailed processes (e.g., "Provide Traffic Surveillance", "Monitor HOV Lane Use"). General processes are defined in terms of more detailed processes using data flow diagrams. The most detailed processes (sometimes called primitives) are defined in Process Specifications (PSpecs).

The textual definition of the most detailed processes identified in the logical architecture view of the National ITS Architecture. The process specification includes an overview, a set of functional requirements, and a complete set of inputs and outputs.

A framework that identifies the institutional agreement and technical integration necessary to interface a major ITS project with other ITS projects and systems.

The geographical area that identifies the boundaries of the Regional ITS Architecture and is defined by and based on the needs of the participating agencies and other stakeholders. In metropolitan areas, a region should be no less than the boundaries of the metropolitan planning area.

A specific, tailored framework for ensuring institutional agreement and technical integration for the implementation of ITS projects or groups of projects in a particular region. It functionally defines what pieces of the system are linked to others and what information is exchanged between them.

As part of the Department of Transportation, the Research and Innovative Technology Administration (RITA) has the responsibility for the strategic direction and management oversight of USDOT’s ITS program, including the National ITS Architecture program.

This document presents an analysis of potential critical risks that may delay or prevent the deployment of ITS technologies, and recommends mitigation plans which will eliminate of reduce these risks to the deployment process. It is intended for implementers that are involved with the details of ITS deployment in their region, throughout the development of the Regional ITS Architecture.