The National Academies

NCHRP 20-64 [Completed]

XML Schemas for Exchange of Transportation Data (TransXML)

  Project Data
Funds: $500,000
Research Agency: Cambridge Systematics, Inc.
Principal Investigator: Eric Ziering
Effective Date: 3/1/2004
Completion Date: 10/1/2006

Project website: http://www.transxml.org/


The planning, design, construction, maintenance, and operation of the transportation infrastructure all require exchanging large volumes of data. Until recently, transportation agencies have been hindered by the lack of common data formats that would facilitate the exchange of data across different platforms and applications. XML (eXtensible Markup Language) has proven to be a universal structured data transfer methodology that facilitates e-Business and e-Government. Originally designed to meet the challenges of large-scale electronic publishing, XML is also playing an increasingly important role in the exchange of a wide variety of data on the web and elsewhere. XML data structures, known as schemas, provide a mechanism to develop and adopt common formats for data exchange.

The XML schemas that are of interest to AASHTO and its member departments typically support transportation infrastructure-related business processes in local, state, and federal departments of transportation (DOTs) as well as the work of their partners. These schemas are of equal interest to vendors who develop software products to support the transportation industry. There are currently several open consortia of private- and public-sector organizations working to create schemas to support the transportation industry, including LandXML, aecXML, ITS XML, and OpenGIS. For some transportation applications, XML schemas do not yet exist, but their availability would facilitate the exchange of transportation data broadly across multiple business areas in a format independent of the software that produced it. However, there is no formal mechanism or framework within the transportation community to develop and maintain XML schemas, promote schema consistency and acceptance, solicit broader input, and build consensus.

There is a need for development and long-term support of XML schemas for exchange of transportation data that are widely accepted, thoroughly documented, and published on the Internet for access by any organization or individual. The long-term vision is an overall set of XML schema for transportation applications in a framework to be called TransXML.


The objectives of this project were to develop broadly accepted public domain XML schemas for exchange of transportation data and to develop a framework for development, validation, dissemination, and extension of current and future schemas.

Accomplishment of the project objectives required the following tasks.


PHASE 1 (1.) Develop a website to post goals, plans, status, work in progress, final deliverables, names of participants and partners, outcomes, and other information on this project. (2.) Identify the significant business areas in surface transportation with data-exchange requirements that either currently employ XML schema or would benefit from their development. (3.) Review and summarize the status of existing work to create transportation XML schemas including, but not limited to, the following: LandXML, aecXML, JusticeXML, OpenGIS, Traffic Model Markup Language (TMML), AASHTOWare, and emerging ITS XML data standards, such as location referencing and advanced traveler information systems. Considering this earlier work, identify specific existing schemas in the public domain that can be incorporated into an overall set of XML schemas for transportation applications to be called TransXML. Identify and justify criteria used for inclusion of schemas in TransXML. (4.) Identify organizations and agencies that could accept long-term responsibility for TransXML and document the relative advantages and disadvantages of each. It is anticipated that AASHTO will play a major role in TransXML, assisted and supported by other partners. (5.) Identify and prioritize gaps where specific XML schemas need to be developed or modified in the following four business areas: Survey/Roadway Design (including schemas created through LandXML); Transportation Construction/Materials; Highway Bridge Structures; and Transportation Safety (e.g., crash reporting and analysis systems). (6.) Prepare a plan for the full development of these schemas in Phase 2 of the project. It is expected that the new schemas will be developed by the contractor in collaboration with industry, government agencies, and other stakeholders. The plan should indicate how documentation and data definitions will be addressed and identify naming conventions for XML tags. The plan should identify the scope and level of effort that will be included in each business area, recommend which specific schemas are to be developed in this project, and explain how a consensus on new schemas will be achieved with the stakeholder community. The schemas should be in a format and documented in sufficient detail to meet the submittal and approval requirements for the World Wide Web Consortium (W3C).
(7.) Develop a moderated web-based collaboration tool for stakeholders to use in reviewing, commenting on, and submitting proposed schema additions and modifications. The tool should automatically notify stakeholders of upcoming plans and current activities where review, approval, or other action is needed. It should allow government or private-sector stakeholders to participate in the review and comment process on an ongoing basis. This collaboration tool is distinguished from the website developed in Task 1, which is considered to be primarily a dissemination tool. (8.) Submit an interim report, within 6 months, to document Tasks 1 through 7 for review by the NCHRP. The contractor will be expected to meet with the NCHRP panel approximately 1 month later. A decision whether or not to proceed with any or all of proposed Phase 2 activity will be made by the NCHRP. The contractor shall not begin work on Phase 2 without NCHRP approval.

PHASE 2 (9.) Develop and submit the XML schemas outlined in the Task 6 plan and approved by the NCHRP. It is expected that some existing XML schemas are currently at a sufficiently advanced stage of development that they can be submitted to stakeholders for review and forwarded by AASHTO for W3C acceptance early in Phase 2. (10.) Deliver or develop web-based software that validates whether submitted schemas meet TransXML schema requirements. The software should be made available to users at no cost on the website developed in Task 7 and should be provided shortly after the first XML schema is submitted to the NCHRP. (11.) Provide and document software source code and sample data that can be used to (1) demonstrate examples of the use of schemas for importing, exporting, and accessing data structures and (2) extract metadata from the schemas for the composition of global data dictionaries. The software should include examples in each of the four business areas using "real-life" state DOT applications in at least three different program languages. The proposal should include a description of the scope and description of the expected software. (12.) Recommend a framework (institutional structure and process) that can be used to support continued schema improvement and the development of future schemas that address the business functions of other transportation business areas. (13.) Prepare recommendations on how responsibility for the funding, management, and maintenance of TransXML can be sustained in the future through appropriate institutional arrangements. As noted in Special Note B, include an implementation plan to publicize and encourage the development and sustained use of TransXML. (14.) Submit a final report that documents the entire research effort and deliver the Task 9 XML schemas, the Tasks 10 and 11 software programs and data, and the Tasks 1 and 7 websites as electronic source code. In addition, provide a companion executive summary that outlines the research results. The deliverables should also include a PowerPoint presentation on the background, method, and results of the project. (15.) Deliver a presentation on the project at a meeting of the AASHTO Administrative Subcommittee on Information Systems.

Status: The project has been completed. 

Product Availability: The final report has been published as NCHRP Report 576.

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