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Regional ITS Architecture Guidance Document

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1 Introduction

Intelligent Transportation Systems have been defined as: "the application of advanced sensor, computer, electronics, and communication technologies and management strategies—in an integrated manner—to improve the safety and efficiency of the surface transportation system". This definition encompasses a broad array of systems and information processing and communications technologies. In order to fully incorporate ITS into the surface transportation network, ITS must be "mainstreamed" into the overall transportation planning and project development processes that exist in each state and metropolitan region of the country.

In 1997, Congress passed the Transportation Equity Act for the 21st Century (TEA-21) to address the need to begin to work toward regionally integrated transportation systems. In January 2001, FHWA published FHWA Rule 940 (23 CFR Part 940), and FTA published a companion policy, to implement section 5206(e) of TEA-21. This Rule/Policy seeks to foster regional integration by requiring that all ITS projects funded from the Highway Trust Fund be in conformance with the National ITS Architecture and officially adopted standards. "Conformance with the National ITS Architecture" is defined in the final Rule/Policy as using the National ITS Architecture to develop a "regional ITS architecture" that would be tailored to address the local situation and ITS investment needs, and the subsequent adherence of ITS projects to the regional ITS architecture. The Rule/Policy remains in effect with the most recent SAFETEA-LU surface transportation authorization act and includes new provisions and considerations. Section 1201.c of the SAFETEA-LU legislation requires State and local governments to address information needs and data exchange associated with highway and transit information and monitoring systems when developing or updating their regional ITS architectures. Section 6001 of SAFETEA-LU mandates that large metropolitan areas (population greater than 200,000) establish a congestion management process (CMP). This process needs to provide for effective management and operation of the transportation system within the region. The CMP is something that can be greatly enhanced by receiving archived ITS travel data, among other data points, generated by a deployed ITS network. During the stakeholder identification process, the ITS architecture should include this planning need for ITS data throughout the region. ITS architectures provide support in these areas as stakeholders analyze their implementation.

The objective of this document is to provide guidance on the development, use, and maintenance of regional ITS architectures. The document presents a process for creating a regional ITS architecture and provides sample outputs of each aspect of the regional ITS architecture. In its discussion of the uses of the regional ITS architecture the document presents an approach for mainstreaming ITS into the planning and project development processes. Although this document focuses on regional ITS architecture it recognizes that the real value of this architecture is as a tool to support the planning and project development processes.

Transportation planning is an ongoing, iterative process, whose goal is making quality, informed decisions pertaining to the investment of public funds for regional transportation systems and services. A regional ITS architecture (created with the use of the planning information already developed) can be a powerful tool for planning the regional integration of transportation systems. Indeed the very process of creating a regional ITS architecture can enhance regional planning by bringing together a diverse array of agencies and stakeholders to discuss future transportation needs and how these needs might be met by ITS.

This document is intended for anyone who is involved, or will be involved in the development, use or maintenance of regional ITS architectures. Because of the detailed nature of the discussion of the architecture development process and architecture outputs, the document is most applicable for those transportation professionals who will lead or play a key role in the development or use of a regional ITS architecture.

Although this document provides guidance on the entire process, those that have already accomplished many of the process steps, including those that already have completed a regional ITS architecture, may also find the document to be useful. Stakeholders who are coming in at a later step will find a wealth of best practices information and examples from around the country that may influence their on-going regional ITS architecture-related activities.

Is knowledge of architecture in general or the National ITS Architecture in specific required to read and use this document? Not if the reader wishes to gain a general understanding of the process of developing and using a regional ITS Architecture. But to understand the details of the process of developing an architecture, and to actually develop a regional ITS architecture using the process, the reader should have some baseline knowledge of the National ITS Architecture.

1.1 What is an ITS Architecture?

An architecture defines a framework within which a system can be built. It functionally defines what the elements of the system do and the information that is exchanged between them. An architecture is important because it allows integration options to be considered prior to investment in the design and development of the elements of the system. 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. The functions the system performs remain the same while technology evolves.

Intelligent Transportation Systems (ITS) are interrelated systems that work together to deliver transportation services. Integration of these systems requires an architecture to illustrate and gain consensus on the approach to be taken by a group of stakeholders regarding their particular systems. An ITS Architecture defines the systems and the interconnections and information exchanges between these systems.

The primary components of an ITS Architecture are Subsystems and Information Flows:

Two different types of ITS Architectures are discussed in this document:

This document describes a process for defining a regional ITS architecture using the National ITS Architecture as a resource. There are numerous advantages to using the National ITS Architecture as the basis for creating a regional ITS Architecture. Primary among these is a significant savings of time and cost because the National ITS Architecture represents a very complete framework of ITS services, has already undergone considerable stakeholder review, and has a variety of tools to assist the user in creating a regional ITS architecture. These tools will be further discussed in later sections of this document.

A thorough understanding of the terms and concepts of the National ITS Architecture is important to key stakeholders who are involved in the creation of a regional ITS architecture using the process described in this document. In providing guidance on this process, the document makes liberal use of these terms and concepts, so this knowledge is required for the reader to fully understand the guidance provided.

ResourcesFor those readers who are unfamiliar with the National ITS Architecture, all the terms that are used in this document are defined in Appendix B. This is probably sufficient for the reader who wishes to gain a general understanding of the process of developing and using a regional ITS Architecture. To understand the details of the process of developing a regional ITS architecture, and to actually develop a regional ITS architecture using the process, the reader should have some introductory training in the National ITS Architecture. Additional information on the National ITS Architecture as well as information on available training can be found at the FHWA's ITS Joint Program Office website: http://www.its.dot.gov/arch/index.htm.

1.2 The Goal of a Regional ITS Architecture

State and local governments and transportation organizations apply transportation tools to address transportation issues on a regional basis. Each region has unique needs and is affected, in some manner, by neighboring regions. ITS is one of these transportation tools. It harnesses the valuable information generated by various subsystems within and around a region to better manage and operate the transportation system as a whole.

The purpose of developing a regional ITS architecture is to illustrate and document regional integration so that planning and deployment can take place in an organized and coordinated fashion. Typically, a region contains multiple transportation agencies and jurisdictions. These may have both adjoining and overlapping geographies, but the common thread for all of the agencies is the need to provide ITS solutions to transportation problems such as traffic congestion and safety hazards. It is important that these solutions be provided economically, utilizing public funds in a responsible manner.

Regional integration allows for the sharing of information and coordination of activities among regional transportation systems to efficiently and effectively operate. Regional integration may also have a synergistic effect on transportation systems (e.g. information from one system may be used by another system for a different purpose. An example of this would be transit AVL data being used by a freeway management center as probe data to obtain speed information on freeway segments traveled by the transit vehicles.) A regional ITS architecture illustrates this integration and provides the basis for planning the evolution of existing systems and the definition of future systems that facilitate the integration over time.

For the private sector, opportunities exist to develop information systems providing value-added services to the traveling public. Participating in the development of a regional ITS architecture can highlight needs for data integration between public and private partners. It can also identify ways in which public sector agencies can benefit from information that the private sector has.

This regional integration can only take place with the participation and cooperation of the organizations within a region. These stakeholders must work together to establish a regional ITS architecture that reflects a consensus view of the parties involved. A regional ITS architecture's most important goal is institutional integration; providing a framework within which regional stakeholders can address transportation issues together.

1.3 Using a Regional ITS Architecture

A regional ITS architecture is a useful tool for planning and implementing ITS within a region. From a planning perspective, the regional ITS architecture defines the ITS that the regional stakeholders wish to realize over a given timeframe. This plan for ITS in the region will be realized in an incremental fashion as funding and/or technology is available and institutional issues are resolved. ITS projects are defined to achieve the regional plan, using the regional ITS architecture to properly and efficiently define projects so that they build upon one another.

A regional ITS architecture can identify opportunities for making ITS investments in a more cost-effective fashion, by utilizing inter-agency cooperation during planning, implementation, and operation of these ITS projects.

Due to the regional and local variations in the practice of transportation planning, local stakeholders must decide how best to incorporate the regional ITS architecture and the products produced during its development into the Transportation Planning Process, and vice versa.

For the region’s Metropolitan Planning Organization (MPO) and for other area-wide and statewide planning agencies and authorities, the regional ITS architecture will provide information for updating the Long Range Plan, the Transportation Improvement Program (TIP) and other capital plans.  It will also provide information for use in other planning studies and activities, including the Congestion Management Plan, Corridor and Sub-Area Studies, performance-monitoring activities, transit development plans, and other locally defined studies or plans.  For statewide planning agencies, it will provide information for updating the Statewide TIP, the State Implementation Plan (SIP), and other statewide or multi-region plans and studies.

Once ITS projects are programmed, the regional ITS architecture provides a starting point for project development.  It provides initial inputs to support the systems engineering process including the establishment of the concept of operations, requirements, and high-level design and test planning of ITS projects.  The regional ITS architecture improves continuity across the project lifecycle, from planning through project development and operations.

The regional ITS architecture can also be useful to private companies contemplating ITS investments, by helping them understand long-range and short-range ITS planning goals of the local public sector agencies, plus the technical and institutional context in which any private investments would be made.

In Transportation Planning, a regional ITS architecture has its greatest impact on institutional integration.  It provides a structure around which discussions can take place among regional stakeholders to gain consensus on the direction of ITS.  It implies roles and responsibilities for each stakeholder involved to realize the benefits of ITS within the region.

1.4 USDOT Policy

Rule/PolicyOn January 8, 2001, the US Department of Transportation published the FHWA Final Rule and FTA Policy, which implement section 5206(e) of the Transportation Equity Act for the 21st Century (TEA-21). The Final Rule/Policy, effective April 8, 2001, explains and defines how Section 5206(e) is to be implemented. TEA-21 required ITS projects funded through the highway trust fund to conform to the National ITS Architecture and applicable standards. The intention of the Rule/Policy is to foster the deployment of integrated regional ITS systems.

Because it is highly unlikely that the entire National ITS Architecture would be fully implemented by any single metropolitan area or State, the Rule/Policy requires that the National ITS Architecture be used to develop a local implementation or "regional ITS architecture" that would be tailored to address the local situation and ITS investment needs. The region is defined by local participants and is based on the needs for information sharing and coordination. It can be a metropolitan area, a state, a multi-state area, or a corridor.

The Rule/Policy requires that if a region is already deploying ITS projects, then a regional ITS architecture must be developed within four years of the effective date of the Rule/Policy (by April 8, 2005). If a region has not yet deployed an ITS project then a regional ITS architecture must be developed within four years of the deployment of the initial ITS project in the region. The intention of the new Rule/Policy is to foster integration of the deployment of regional ITS systems.

This guide makes frequent reference to the Rule/Policy requirements for regional ITS architectures, describing how the specific process steps and products relate to the Rule/Policy. In addition to the regional ITS architecture requirements, the Rule/Policy also includes requirements for ITS Project Implementation and Project Administration, which are not addressed in detail by this document.

ResourcesFurther information on the Intelligent Transportation System Architecture and Standards Policy/Rule can be found at http://www.ops.fhwa.dot.gov/its_arch_imp/policy.htm.


1.5 How This Document is Organized

Section 2 of the document identifies a candidate regional ITS architecture development process. Sections 3 through 6 elaborate on steps within the overall process and identify examples of the products of the process. Section 7 discusses regional ITS architecture use and section 8 addresses maintenance of a regional ITS architecture.

About the Examples

The examples that are used throughout the document were drawn from actual regional ITS architectures that have been developed for small, medium, and large metropolitan areas and rural regions around the country. In a few cases, examples were created to illustrate a process step or output when a real example was not available. A few of the real world examples were created prior to publication of the Rule/Policy on Architecture and Standards, but the examples that are included meet the intent of the guidance.

About the Icons

This document uses icons to highlight different kinds of information. The icons can help you find particular types of information within the document.

TipThis icon identifies suggestions that may improve the regional ITS architecture development effort or the quality of the products that are generated. Usually based on actual experience, these are ideas that have worked in the past.

CautionThis icon flags warnings. In contrast to tips, these are problems that have been encountered that you should avoid. Also frequently based on actual experience, these are ideas that have NOT worked in the past.

ResourcesThis icon signals ITS resources that offer additional information related to regional ITS architectures. Normally, a specific web site address and/or an Electronic Document Library number are provided for these resources. If you don't find the resources you need here, the "ITS Resource Guide" is an excellent general source of information. It is available on-line at http://www.its.dot.gov/guide.htm.

Rule/PolicyThis icon highlights references to the FHWA Final Rule and FTA Policy on ITS Architecture and Standards. These are normally specific references to paragraphs that are most relevant to the particular process step or product. Additional information on the Rule/Policy is available at: http://www.ops.fhwa.dot.gov/its_arch_imp/policy.htm.

National ITS ArchitectureThis icon identifies information about the National ITS Architecture. Specific information is provided on different parts of the National ITS Architecture and how they apply to particular regional ITS architecture development steps. Visit http://www.its.dot.gov/arch/arch_howto.htm for information on how to order a CD-ROM and a variety of other links and current National ITS Architecture news and information. An on-line version of the Architecture is available at http://www.its.dot.gov/arch/index.htm. Several training courses on the National ITS Architecture are available from the National Highway Institute. See http://www.nhi.fhwa.dot.gov/Home.aspx for more information.

SecurityThis icon is used to flag security-related information in the document. Security is an important factor to consider throughout the regional ITS architecture development. Identified passages explain where security may impact steps in the regional ITS architecture development process.

TurboThis icon is associated with specific information on the Turbo Architecture software tool. Normally, the passage explains how Turbo Architecture can be used to support a particular step in the regional ITS architecture development process.

Turbo Architecture is an interactive software program that allows transportation professionals to use the information defined in the National ITS Architecture to create a regional or project architecture that reflects the transportation needs of the region. Additional information about Turbo Architecture, including information on how to obtain a copy, is contained in Appendix A. A Turbo Architecture training course is offered through the National Highway Institute. See http://www.nhi.fhwa.dot.gov/home.aspx for more information.

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