See element.

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.

Access point for four Web-based resources that provide ready access to information supporting informed decision making regarding deployment and operations of ITS to improve transportation system performance. The four knowledge resources are the ITS Benefits Database, ITS Costs Database, ITS Deployment Statistics Database, and the ITS Lessons Learned Knowledge Resource. A fifth Web site, the ITS Applications Overview, provides access to information from each of the knowledge resources using an organization structure. The ITS Knowledge Resource Portal is available at www.ITSKnowledgeResources.its.dot.gov.

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) Research and Innovative Technology Administration (RITA) established to oversee and guide the multi-modal National ITS program.

Existing transportation systems, communications systems, and institutional processes.

A measure of the quality of the operation of different roadway types defined in the Highway Capacity Manual (HCM). There are six LOS grades ranging from LOS A, representing optimum operation, to LOS F, representing congested or unstable flow.

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

The part of the National ITS Architecture that 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.

A document of the National Architecture that 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.

Also referred to as the "Transportation Plan", a document resulting from regional or statewide collaboration and consensus on a region’s or state’s transportation system, and serving as the defining vision for the region’s or state’s transportation systems and services. In metropolitan areas, this is the official multimodal transportation plan addressing no less than a 20-year planning horizon that is developed, adopted, and updated by the MPO through the metropolitan transportation planning process.

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 geographic area determined by agreement between the metropolitan planning organization (MPO) for the area and the Governor, in which the metropolitan transportation planning process is carried out.

The policy board of an organization created and designed to carry out the metropolitan transportation planning process for urbanized areas with populations greater than 50,000, and designated by local officials and the Governor of the state.

The official multimodal, long-range transportation plan addressing no less than a 20-year planning horizon that is developed, adopted and updated by the Metropolitan Planning Organization (MPO) through the metropolitan transportation planning process.

A document of the National Architecture that, as the first of the technical documents, 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.

Index of the ability of users of a system to move defined as [Ton-miles of travel] / [Vehicle-miles of travel * Average speed].

A specific form of transportation, such as automobile, subway, bus, rail, air, bicycle, or foot.

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.

In long range transportation plans, specific, measurable statements related to the attainment of goals.

A component of a regional architecture that identifies the roles and responsibilities of participating agencies and stakeholders. It defines the institutional and technical vision for the region and describes how ITS will work at a very high-level, frequently using operational scenarios as a basis.

Based on a visual survey of the pavement, a numerical index of 0 to 100 to indicate the condition of the pavement on a roadway with 100 representing an excellent pavement.

A document of the National Architecture that 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.

Indicator of how well the transportation system is performing with regard to such measures as average speed, reliability of travel, and accident rates. Used as feedback in the decisionmaking process.

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.

A document of the National Architecture that 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.

As specified in the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) legislation (in Section 5303 and Section 5304 of Title 49 of the United States Code), the nine areas which metropolitan planning organizations (MPOs) and states should consider when developing their transportation plans.

A joint effort between planners and operators to support improved regional transportation system management and operations that involves a variety of activities that lead to improved transportation system operations, including the consideration of management and operations strategies in the transportation planning process.

A measure of the amount of extra time that travelers need to add to free-flow (or posted speed limit) travel time in order to arrive on-time in almost all situations (i.e. 95% of the time). The planning time index takes into account both recurring and non-recurring sources of delay. The planning time index is calculated as 95th percentile travel time (in minutes) / Travel time at free flow speed or posted speed limit (in minutes).

A function or activity identified in the logical architecture 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 of the National ITS Architecture. The process specification includes an overview, a set of functional requirements, and a complete set of inputs and outputs.

The process used to implement a project. Typically for traditional transportation construction project involves phases of project initiation, preliminary engineering, plan development, construction and project closeout. Also referred to as project deployment or project implementation.

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.

A document of the National Architecture that presents an analysis of potential critical risks that may delay or prevent the deployment of ITS technologies, and recommends mitigation plans which will eliminate or 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.

A combination of technologies that collects, transmits, models, and disseminates weather and road condition information.A term used in transit operations to describe an operator work assignment.

A term used in transit operations to describe an operator work assignment.

Legislation passed in 2005 that authorized the federal surface transportation programs for highways, highway safety, and transit.