term_Architecture="A framework within which a system can be built.  Requirements dictate what functionality the architecture must satisfy.  An architecture functionally defines what the pieces of the system are and the information that is exchanged between them.  An architecture is functionally oriented and not technology-specific which allows the architecture to remain effective over time.  It defines 'what must be done,' not 'how it will be done.'"
term_Architecture_Flow="Information that is exchanged between subsystems and terminators in the physical architecture of the National ITS Architecture. Architecture flows are the primary tool that is used to define interfaces in regional ITS architectures and project ITS architectures.  Architecture flows and their communication requirements define the interfaces which form the basis for much of the ongoing standards work in the national ITS program.  The terms 'information flow' and 'architecture flow' are used interchangeably."
term_Architecture_Interconnect="Communications paths that carry information between subsystems and terminators in the physical architecture of the National ITS Architecture.  Several different types of interconnects are defined in the National ITS Architecture to reflect the range of interface requirements in ITS.  The majority of the interconnects are various types of communications links that are defined in the communications layer.   Four different types of communications links are defined: Fixed Point - Fixed Point Communications, Wide Area Wireless (Mobile) Communications, Field - Vehicle Communications, and Vehicle - Vehicle Communications.  In addition to these types, several specialized interconnects are also defined to reflect other interface requirements.  These include human interface (e.g., what the system user sees and hears) and physical/environmental (e.g., what the ITS sensors sense)."
term_Block="A term used in transit operations to describe a vehicle work assignment, i.e. a sequence of trips made by a single bus. Blocks can be divided between different operators."
term_Browser="A type of software that allows viewing of and navigation through HTML pages."
term_Buffer_Index="See travel time buffer index."
term_Center_Subsystems="Subsystems that provide management, administrative, and support functions for the transportation system.  The center subsystems each communicate with other centers to enable coordination between modes and across jurisdictions.  Some examples of center subsystems are Traffic Management, Transit Management, Commercial Vehicle Administration, Archived Data Management, Emissions Management, Toll Administration, Emergency Management, Information Service Provider, and Fleet and Freight Management.  The Center subshystems class is one of four general subsystem classes defined in the National ITS Architecture."
term_Clarus_System="A network for sharing and exchanging surface weather data<br />and relevant surface transportation conditions.  It provides a one-stop, Internet-based portal for all surface transportation environmental observations."
term_Clean_Air_Act__CAA_="The original Clean Air Act was passed in 1963, but the national air pollution control program is actually based on the 1970 revision of the law. The Clean Air Act as amended in 1990 made major changes and contains the most farreaching revisions of the 1970 law."
term_Communications_Document="A document of the National Architecture that provides a thorough analysis of the communications requirements of the National ITS Architecture, and ITS in general, and includes a discussion of options for implementing various communications links.  It is an important document for those involved in detailed design and integration during the systems engineering process."
term_Communications_Layer="One of three layers (along with the transportation and institutional layers) defined by the National ITS Architecture.  The communications layer includes all of the communications equipment (e.g., wireline and wireless transmitters and receivers) and the information management and transport capabilities necessary to transfer information among entities in the transportation layer.  The application data content and the transportation application requirements are generally transparent to the communications layer.  The communication layer's view of ITS is that of many distributed users, some of them mobile, which require communication services."
term_Concept_of_Operations__Con_Op_="For a specific project, the document in which the project stakeholders document their shared understanding of the system to be developed and how it will be operated and maintained."
term_Congestion_Management_Process__CMP_="A systematic approach required in transportation management areas (TMAs) that provides for effective management and operation, based on a cooperatively developed and implemented metropolitan-wide strategy of new and existing transportation facilities eligible for funding under title 23 U.S.C. and title 49 U.S.C. through the use of operational management strategies. Provides information on transportation system performance and finds alternative ways to alleviate congestion and enhance the mobility of people and goods, to levels that meet state and local needs."
term_Control_Delay="For signalized intersections, the portion of the total delay attributed to traffic signal operation."
term_Cost_Analysis="A document of the National Architecture that has two purposes.  First, it develops a high level cost estimate of the expenditures that are associated with implementing ITS components.  Second, it is a costing tool for implementers, by providing unit prices and systems costs of ITS subsystems.  There is significant correlation between the Cost Analysis and the Evaluatory Design documents; the cost analysis is based largely on the assumptions made for the three deployment scenarios (urban, interurban, and rural)."
term_Data_Dictionary_Entry__DDE_="Every data flow included in the logical architecture of the National ITS Architecture is defined in a data dictionary entry.  Each data dictionary entry contains a textual description of the data flow and identifies any lower level data elements that make up the data flow."
term_Data_Flow="Representations of data flowing between processes or between a process and a terminator in the logical architecture of the National ITS Architecture.  A data flow is shown as an arrow on a data flow diagram and is defined in a data dictionary entry in the logical architecture.  Data flows are aggregated together to form high-level architecture flows in the physical architecture of the National ITS Architecture."
term_Data_Flow_Diagram__DFD_="The diagrams in the logical architecture of the National ITS Architecture that show the functions that are required for ITS and the information that moves between these functions.  Only four different symbols are used on the diagrams.  Circles represent the processes or functions that do the work.  Arrows represent the data flows that show how data moves through the system.  Parallel lines represent data stores that represent 'data at rest' in the system.  Finally, rectangles represent the terminators that define the architecture boundary.  A hierarchy of these diagrams depict the ITS functionality and data flow requirements in successively greater detail until 'primitive' processes are defined."
term_Data_Store="A data store represents a reservoir in which data can be held for an indefinite period.  Data stores are shown on the data flow diagrams where data repositories are required to support data aggregation or archival services."
term_Element="An ITS system or piece of a system named as the name used by stakeholders. Elements are the basic building blocks of regional ITS architectures and project ITS architectures."
term_EMF="Enhanced Metafile. A graphics file format, originated by Microsoft Corporation, that has many advantages over the older Windows metafiles (WMF).  Images in EMF format can be resized without distortion and loss of detail. Available for download for selected diagrams (e.g., subsystem and terminator diagrams).  Many diagrams displayed on the National ITS Architecture CD-ROM and web site are actually in GIF format."
term_Equipment_Package="The building blocks of the subsystems of the physical architecture subsystems. Equipment packages group similar processes of a particular subsystem together into an 'implementable' package.  The grouping also takes into account the user services and the need to accommodate various levels of functionality.  The equipment packages were used as a basis for estimating deployment costs (as part of the evaluation that was performed).  Since equipment packages are both the most detailed elements of the physical architecture of the National ITS Architecture and tied to specific service packages, they provide the common link between the interface-oriented architecture definition and the deployment-oriented service packages."
term_Evaluation_Results="A document of the National Architecture that contains a concise summary of the various evaluations that were performed in five other National ITS Architecture documents: Evaluatory Design, Communications Document, Cost Analysis, Performance and Benefits Study, and Risk Analysis."
term_Evaluatory_Design="A document of the National Architecture that supports evaluation of the National ITS Architecture's performance, benefits, and costs for three conceptual scenarios at various points in time.  The scenarios consist of 'typical' deployment environments: urban, inter-urban, and rural.  The entire document will assist you in developing an evaluation methodology for the architecture that you have developed for your particular region or project."
term_Executive_Summary="A document of the National Architecture that provides an overview of the most important aspects of the National ITS Architecture including the logical architecture, physical architecture and the implementation strategy."
term_Federal_Highway_Administration__FHWA_="An agency of the United States Department of Transportation.  FHWA administers the Federal-aid Highway Program, which provides financial assistance to States to construct and improve highways, urban and rural roads, and bridges. FHWA also administers the Federal Lands Highway Program, which provides access to and within national forests, national parks, Indian Tribal lands, and other public lands. FHWA is headquartered in Washington, DC, with field offices across the country, including one in or near each State capital."
term_Federal_Transit_Administration__FTA_="An agency of the United States Department of Transportation.  FTA is the principal source of Federal financial assistance to America's communities for the planning, development, and improvement of public or mass transportation systems. FTA provides leadership, technical assistance, and financial resources for safe, technologically advanced public transportation that enhances mobility and accessibility, improves the nation's communities and natural environment, and strengthens the national economy. FTA is headquartered in Washington, DC, with regional offices in Atlanta, Boston, Chicago, Dallas, Denver, Kansas City, New York, Philadelphia, San Francisco, and Seattle."
term_Field___Vehicle_Communications="A wireless communications channel used for close-proximity communications between vehicles and the immediate infrastructure. It supports location-specific communications for ITS capabilities such as toll collection, transit vehicle management, driver information, and automated commercial vehicle operations.  One of the types of architecture interconnects defined in the National ITS Architecture."
term_Field_Subsystems="Intelligent infrastructure distributed along the transportation network which performs surveillance, information provision, and plan execution control functions and whose operation is governed by center subsystems.  Field subsystems also directly interface to vehicle subsystems.  The Field subsystems class is one of the four general subsystem classes defined in the National ITS Architecture."
term_Fixed_Point___Fixed_Point_Communications="A communication link serving stationary entities.  It may be implemented using a variety of public or private communication networks and technologies.  It can include, but is not limited to, twisted pair, coaxial cable, fiber optic,  microwave relay networks, spread spectrum, etc.  In Fixed Point - Fixed Point (FP2FP) communication the important issue is that it serves stationary entities.  Both dedicated and shared communication resources may be used. One of the types of architecture interconnects defined in the National ITS Architecture."
term_Functional_Requirement="A statement that specifies WHAT a system must do. The statement should use formal 'shall' language and specify a function in terms that the stakeholders, particularly the system implementers, will understand. In the National ITS Architecture, functional requirements have been defined for each Equipment Package that focus on the high-level requirements that support regional integration."
term_GIF="Graphic Interchange Format.  A widely used graphics file format, developed by CompuServe.  Many images found on the National ITS Architecture CD-ROM and web site are in GIF format and can be typically be copied by right-clicking on them with your mouse.  Unlike WMF files, GIF files are not well suited for resizing or other modifications."
term_Goals="In long range transportation plans, generalized statements which broadly relate the physical environment to values."
term_High_Occupancy_Vehicle__HOV_="Vehicles carrying two or more people. The number that constitutes an HOV for the purposes of HOV highway lanes may be designated differently by different transportation agencies."
term_HTML="HyperText Markup Language.  A language for marking up documents with a set of tags that designate the design and display intention of the author and how sections or documents are linked together.  These documents are displayed as pages with text and graphics that can be viewed through the use of a browser."
term_Implementation_Strategy="A document of the National Architecture that presents a scheme for implementing ITS services in a phased approach.  This is part of an overall strategy that includes recommendations for future research and development, operational tests, standards activities, and training. <br /><br />The Implementation Strategy analysis and guidance is all based on service packages.  It identifies the service packages that provide certain ITS services and recommends a phased deployment of those service packages to provide the most needed and most feasible user services initially, and less needed/feasible user services at a later date.  The Implementation Strategy considers several items and issues regarding deployment, such as legacy systems, politics, funding, service package synergy, technology requirements, and standards requirements.  <br /> <br />Much of the service package-related analysis that is contained in the Implementation Strategy has been updated and included in the new Service Packages Document.  The Service Packages Document is the authoritative source for all current information on the National ITS Architecture service packages."
term_Information_Flow="Information that is exchanged between subsystems and terminators in the physical architecture of the National ITS Architecture.  The terms 'information flow' and 'architecture flow' are used interchangeably.  Information flows are the primary tool that is used to define the ITS architecture interfaces. These information flows and their communication requirements define the interfaces which form the basis for much of the ongoing standards work in the national ITS program."
term_Institutional_Layer="An integral component of the National ITS Architecture that 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."
term_Intelligent_Transportation_System__ITS_="The system defined as the electronics, communications or information processing in transportation infrastructure and in vehicles used singly or integrated to improve transportation safety and mobility and enhance productivity. Intelligent transportation systems (ITS) encompass a broad range of wireless and wire line communications-based information and electronics technologies."
term_Interconnect="See architecture interconnect."
term_Intermodal="The ability to connect, and connections between, differing modes of transportation."
term_Intermodal_Surface_Transportation_Efficiency_Act_of_1991__ISTEA_="Legislative initiative by the U.S. Congress that restructured and authorized federal funding for transportation programs; provided for an increased role for regional planning commissions/ MPOs in funding decisions; and required comprehensive regional and statewide longterm transportation plans.  Superseded by the Transportation Equity Act for the 21st Century (TEA-21) in 1998."
term_Inventory="See system inventory."
term_Inventory_Element="See element."
term_ITS_Architecture="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."
term_ITS_Knowledge_Resources="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."
term_ITS_Project="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."
term_ITS_Security_Area="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."
term_Joint_Program_Office__JPO_="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."
term_Legacy_System="Existing transportation systems, communications systems, and institutional processes."
term_Level_of_Service__LOS_="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."
term_Life_cycle="A term used when denoting a progression through a series or sequence of differing stages of development."
term_Logical_Architecture="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."
term_Logical_Architecture_Document="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."
term_Long_Range_Transportation_Plan__LRTP_="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."
term_Major_ITS_Project="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."
term_Metropolitan_Planning_Area="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."
term_Metropolitan_Planning_Organization__MPO_="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."
term_Metropolitan_Transportation_Plan__MTP_="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."
term_Mission_Definition="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."
term_Mobility_Index="Index of the ability of users of a system to move defined as [Ton-miles of travel] / [Vehicle-miles of travel * Average speed]."
term_Mode="A specific form of transportation, such as automobile, subway, bus, rail, air, bicycle, or foot."
term_National_ITS_Architecture="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)."
term_National_Program_Plan="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."
term_Objectives="In long range transportation plans, specific, measurable statements related to the attainment of goals."
term_Operational_Concept="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."
term_Pavement_Condition_Index="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."
term_Performance_and_Benefits_Study="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."
term_Performance_Measure="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."
term_Physical_Architecture="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."
term_Physical_Architecture_Document="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."
term_Physical_Entities="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."
term_Planning_Factors="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."
term_Planning_for_Operations="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."
term_Planning_Time_Index="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)."
term_Process="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)."
term_Process_Specification__pspec_="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."
term_Project_Development="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."
term_Project_ITS_Architecture="A framework that identifies the institutional agreement and technical integration necessary to interface a major ITS project with other ITS projects and systems."
term_Region="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."
term_Regional_ITS_Architecture="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."
term_Research_and_Innovative_Technology_Administration__RITA_="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."
term_Risk_Analysis="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."
term_Road_Weather_Information_System__RWIS_="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."
term_Run="A term used in transit operations to describe an operator work assignment."
term_Safe,_Accountable,_Flexible,_Efficient_Transportation_Equity_Act:_A_Legacy_for_Users__SAFETEA_LU_="Legislation passed in 2005 that authorized the federal surface transportation programs for highways, highway safety, and transit."
term_Scalable_Vector_Graphics="Scalable Vector Graphics (SVG) is a language for describing two-dimensional graphics and graphical applications that is backed by the World Wide Web Consortium.  Graphics described in SVG file format can be scaled without losing graphic quality.  SVG files can be compressed to accommodate faster downloads of the graphic.  The National ITS Architecture uses compressed SVG format to view the data flow diagrams (DFDs) from the logical architecture.  The first time you open one of these diagrams you may be prompted to download an SVG Viewer as an add-on to your existing Web Browser."
term_Securing_ITS="The protection of ITS itself is comprised of security services that protect ITS systems and the communications between them.  See the Security Document for more information."
term_Security_Document="A document of the National Architecture that presents an overview of the topic of security in the National ITS Architecture.  It provides the context and considerations for using the security-related parts of the National ITS Architecture.  This document also provides high-level guidance to agencies that desire to include security considerations in their regional ITS architectures and project ITS architectures.  In addition to defining eight functional security areas as part of the National ITS Architecture, this document also discusses securing ITS itself."
term_Security_Objective="Providing security for the surface transportation system has a set of desired outcomes (or objectives).  How well a security system performs can be measured by the extent to which it meets the desired objectives."
term_Security_Services="Security services are typical security mechanisms or countermeasures that provide for different aspects of security."
term_Security_Threat="Security threats are events or circumstances that adversely impact a surface transportation system or communication between systems."
term_Service_Package="The service packages, formerly known as 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. Service packages collect together one or more equipment packages that must work together to deliver a given ITS 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 ITS service.  Service packages are implemented through projects (or groups of projects, aka programs) and in transportation planning, are directly related to ITS strategies used to meet regional goals and objectives."
term_Service_Packages_Document="A document of the National Architecture that expands upon the service package discussion in the Implementation Strategy document by providing a comprehensive review of each of the service packages describing how service 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 service packages can be applied in regional ITS architecture and project ITS architecture development activities. Through these definitions, analyses, and examples, the Service Packages document provides a comprehensive review of the service packages and how they can be used to plan and implement integrated transportation systems customized to local needs."
term_Stakeholders="A widely used term that notates a public agency, private organization or the traveling public with a vested interest, or a 'stake' in one or more transportation elements within a regional ITS architecture or project ITS architecture."
term_Standards="Documented technical specifications sponsored by a Standards Development Organization (SDO) to be used consistently as rules, guidelines, or definitions of characteristics for the interchange of data.  A broad array of ITS standards is currently under development that will specifically define the interfaces identified in the National ITS Architecture."
term_Standards_Development_Plan="A document of the National Architecture that discusses the issues that are involved in the development of system interface standards. It was primarily intended as a planning document for US DOT and the Standards Development Organizations."
term_Statewide_Transportation_Improvement_Program__STIP_="A statewide prioritized listing/program of transportation projects covering a period of at least four years that is consistent with the long-range statewide transportation plan (LRSTP), metropolitan transportation plans (MTPs), and transportation improvement plans (TIPs), and is required for projects to be eligible for funding under title 23 U.S.C. and title 49 U.S.C. Chapter 53."
term_Statewide_Transportation_Plan="The official statewide multimodal, long-range transportation plan addressing no less than a 20-year planning horizon that is developed, adopted and updated by the state DOT through the statewide transportation planning process."
term_Subsystem="The principle structural element of the physical architecture of the National ITS Architecture.  Subsystems are individual pieces of the Intelligent Transportation System defined by the National ITS Architecture.  Subsystems are grouped into four classes: Centers, Field, Vehicles, and Travelers. Example subsystems are the Traffic Management Subsystem, the Vehicle Subsystem, and the Roadway Subsystem. These correspond to the physical world: respectively traffic operations centers, automobiles, and roadside signal controllers.  Due to this close correspondence between the physical world and the subsystems, the subsystem interfaces are prime candidates for standardization."
term_Subsystem_Diagram="A diagram which depicts all subsystems in the National ITS Architecture and the basic communication channels between these subsystems.  The subsystem diagram is a top-level architecture interconnect diagram.  Variations of the subsystem diagram are sometimes used to depict regional ITS architectures or project ITS architectures at a high level."
term_System="A collection of hardware, software, data, processes, and people that work together to achieve a common goal.  Note the scope of a 'system' depends on one's viewpoint.  To a sign manufacturer, a dynamic message sign is a 'system'.  To a state DOT, the same sign is only a component of a larger Freeway Management 'System'.  In a regional ITS architecture or project ITS architecture, a Freeway Management System is a part of the overall surface transportation 'system' for the region."
term_System_Inventory="The list of all ITS-related elements in a regional ITS architecture or project ITS architecture."
term_Systems_Engineering="Defined by International Council on Systems Engineering (INCOSE) as an interdisciplinary approach and means to enable the realization of successful systems. It focuses on defining customer needs and required functionality early in the development cycle, documenting requirements, and then proceeding with design synthesis and system validation while considering the complete problem.  Systems engineering integrates all the disciplines and specialty groups into a team effort forming a structured development process that proceeds from concept to production to operation. Systems engineering considers both the business and the technical needs of all customers with the goal of providing a quality product that meets the user needs."
term_Terminator="Terminators define the boundary of an architecture.  The National ITS Architecture terminators represent the people, systems, and general environment that interface to ITS.  The interfaces between terminators and the subsystems and processes within the National ITS Architecture are defined, but no functional requirements are allocated to terminators.  The logical architecture and physical architecture of the National ITS Architecture both contain the same set of terminators."
term_Theory_of_Operations="A document of the National Architecture that provides a detailed description of how the National ITS Architecture supports the services described by the Service Packages.  Transaction set diagrams and accompanying narrative are used to provide the detailed description.  These transaction set diagrams provide sequential dependencies among the information flows in each Service Package. It is a technical document, intended for engineers, operators, and others involved in the development of regional ITS architectures or project ITS architectures."
term_Traceability="A cornerstone of the National ITS Architecture is the traceability between its components (as shown in the diagram below).  Microsoft Access databases are used to maintain these connections.  The hyperlinked National ITS Architecture relies on this traceability to build the links that allows navigation between user services, logical architecture, and physical architecture."
term_Transportation_Demand_Management__TDM_="Programs designed to reduce demand for transportation through various means, such as the use of public transit and of alternative work hours."
term_Transportation_Equity_Act_for_the_21st_Century__TEA_21_="Legislated in 1998, TEA-21 authorized approximately $217 billion in federal funding for transportation investment for FYs 1998- 2003. Used for highway, transit, and other surface transportation programs. Superseded in 2005 by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) legislation."
term_Transportation_Improvement_Program__TIP_="A prioritized listing/program of transportation projects covering a period of four years that is developed by an MPO as part of the metropolitan transportation planning process, consistent with the metropolitan transportation plan (MTP), and required for projects to be eligible for funding under title 23 U.S.C. and title 49 U.S.C. Chapter 53."
term_Transportation_Layer="One of three layers (along with the communications layer and the institutional layer) defined by the physical architecture.  The transportation layer shows the relationships among the transportation related elements.  It is composed of subsystems for travelers, vehicles, transportation management centers, and field devices, as well as external system interfaces (terminators) at the boundaries."
term_Transportation_Management_Area__TMA_="An urbanized area with a population of 200,000 or more, as defined by the U.S. Bureau of the Census and designated by the Secretary of Transportation, or any additional area where TMA designation is requested by the Governor and the MPO and designated by the U.S. Secretary of Transportation."
term_Transportation_Plan="See Long-Range Transportation Plan."
term_Transportation_Planning_Process="The process of examining travel and transportation issues and needs in an area. It includes a demographic analysis of the community in question, an examination of travel patterns and trends as well as an analysis of alternatives to meet projected future demands and for providing a transportation system that meets the community’s goals and objectives.  Transportation planning is a cooperative process designed to foster involvement by all users of the system. Transportation planning process is required to be organized and directed for urbanized areas by a metropolitan planning organization (MPO) and for the state by the State Department of Transportation (DOT)."
term_Travel_Time_Buffer_In="A measure of the amount of extra time (buffer) that travelers need to add to their average travel time to account for non-recurring delay.  The buffer is the time between the average travel time and nearworst case travel time (95th percentile). The buffer index is stated as a percentage of the average travel time and is calculated as:  Buffer Index (%) = (95th percentile travel time (in minutes) - average travel time (in minutes)) / average travel time (in minutes)."
term_Travel_Time_Index="The ratio of the average travel time during the peak period, using congested speeds, to the off-peak period travel time, using posted or free-flow speeds."
term_Traveler_Subsystems="Equipment used by travelers to access ITS services pre-trip and en-route. This includes equipment that are owned and operated by the traveler as well as equipment that are owned by transportation and information providers.  The Traveler subsystems class is one of four general subsystem classes defined in the National ITS Architecture."
term_Turbo_Architecture="An automated software tool used to input and manage system inventory, service packages, architecture flows and interconnects of a regional ITS architecture and/or multiple project ITS architectures."
term_United_States_Department_of_Transportation__USDOT_="The principal direct federal funding agency for transportation facilities and programs in the United Stated.  Includes the Research and Innovative Technology Administration (RITA), the Federal Highway Administration (FHWA), the Federal Transit Administration (FTA), the Federal Railroad Administration (FRA), and others."
term_User_Service_Requirement="A specific functional requirement statement of what must be done to support the ITS user services.  The user service requirements were developed  specifically to serve as a requirements baseline to drive National ITS Architecture development.  The user service requirements are not to be construed as mandates to system/architecture implementers, but rather are directions to the National Architecture Team.  As a requirements baseline, the user service requirements include little narrative or background material.  For a general introduction to the user services, consult the National Program Plan."
term_User_Services="User services document what ITS should do from the user's perspective. A broad range of users are considered, including the traveling public as well as many different types of system operators. User services, including the corresponding user service requirements, form the basis for the National ITS Architecture development effort. The initial user services were jointly defined by USDOT and ITS America with significant stakeholder input and documented in the National Program Plan. The concept of user services allows system or project definition to begin by establishing the high level services that will be provided to address identified problems and needs.  New or updated user services have been and will continue to be satisfied by the National ITS Architecture over time."
term_User_Services_Bundle="A logical grouping of user services that provides a convenient way to discuss the range of requirements in a broad stakeholder area.  In the National Program Plan's user service requirements, the user services are grouped into eight bundles: <br /><br />Travel and Traffic Management, <br />Public Transportation Management, <br />Electronic Payment, <br />Commercial Vehicle Operations, <br />Emergency Management, <br />Advanced Vehicle Safety Systems,<br />Information Management, and <br />Maintenance and Construction Operations."
term_Vehicle___Vehicle_Communications="Dedicated wireless system handling high data rate, low probability of error, line of sight communications between vehicles.  Advanced vehicle services may use this link in the future to support advanced collision avoidance implementations, road condition information sharing, and active coordination to advanced control systems.  One of the types of architecture interconnects defined in the National ITS Architecture."
term_Vehicle_Miles_Traveled__VMT_="Miles traveled by all vehicles on a roadway."
term_Vehicle_Subsystems="Covers ITS related elements on vehicle platforms. Vehicle subsystems include general driver information and safety systems applicable to all vehicle types. Four fleet vehicle subsystems (Transit, Emergency, Commercial  and Maintenance and Construction Vehicles) add ITS capabilities unique to these special vehicle types.  The Vehicle subsystems class is one of four general subsystem classes defined in the National ITS Architecture."
term_Vision_Statement="A document of the National Architecture that is written in 'magazine style', the Vision Statement sketches a number of possible scenarios of ITS development over the next 20 years.  It describes how travelers and system operators may be able to use and benefit from ITS technologies in their day."
term_Volume_to_Capacity_Ratio__V/C_="Ratio of the volume using a transportation facility to the capacity of that facility."
term_Wide_Area_Wireless__mobile__Communications="A communications link that provides communications via a wireless device between a user and an infrastructure-based system. Both broadcast (one-way) and interactive (two-way) communications services are grouped into wide-area wireless communications in the National ITS Architecture.  These links support a range of services in the National ITS Architecture including real-time traveler information and various forms of fleet communications.  One of the types of architecture interconnects defined in the National ITS Architecture."
term_WMF="Windows Metafile. A graphics file format, originated by Microsoft Corporation.  Images in WMF format can be resized without distortion and loss of detail.  Available for download for selected diagrams (e.g., architecture flow diagrams).  Many diagrams displayed on the National ITS Architecture CD-ROM and web site are actually in GIF format."