TransXML: XML Schemas for Exchange of Transportation Data (2007)

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13 This section reviews prior XML schema and data standards in surface transportation in order to • Identify gaps to be addressed in TransXML, • Identify XML schema that could be immediately incorpo- rated into TransXML, • Document XML schema and standards that could be incor- porated into future schema development efforts under the TransXML umbrella, and • Identify independent standards and XML schema develop- ment efforts that TransXML development should be aware of and/or coordinate with. 3.1 Overview of Existing Schema and Standards There have been a number of efforts, on the part of individ- ual agencies and vendors and involving consortia of public and private organizations, to develop and use transportation- related XML schemas. While significant progress has been made, particularly in the area of geographic data, the trans- portation arena is still at a relatively early stage of XML schema development and adoption. Transportation data standards, which may evolve or be incorporated into XML schema, also are of relevance to this research effort. Transportation data standards are already being used throughout the industry. Often these standards are in the form of data dictionaries that contain standard codes for specific events. These standards are useful for aggregating data at the state and national levels in order to make sense of data coming from disparate sources. They are also essential in organizing and analyzing large volumes of data. This section provides an overview of standards and XML schema efforts in the four TransXML business areas. In addi- tion, the related areas of geographic data and ITS are included here, since these areas may provide important building blocks for TransXML. The schema and standards efforts reviewed are listed in Table 2 and summarized below. Roadway Survey/Design LandXML provides at least partial support for the Design Surveys, Parcel/Boundary, Geometric Design, Construction/ Stakeout, Survey Feature Codes, and Cross Section topics within this business area. LandXML includes specifications for raw and reduced surveying data, surface data, parcel data, and a 3D road model. LandXML also includes a standard for- mat for official electronic design submission. aecXML sup- ports the Pay Item Quantities topic. Two XML initiatives in the Geotechnical area are relevant to the pavement design area (though by no means provide complete coverage for that area). The Traffic and ITS design topic is partially addressed by the Traffic Software Data Dictionary. Construction/Materials The aecXML schema and Trns•port data model address each of the topic areas within the Construction/Materials business area. In addition, XML initiatives sponsored by the American Institute of Steel Construction and the American Iron and Steel Institute address specific materials. The aecXML Infrastructure effort produced a draft schema that addresses communication of pay items from design to estimation sys- tems. This was based on the aecXML common object schema, which provided a broad range of contract, project, and organization elements relevant to construction. The AASHTOWare Trns•port suite uses XML schema for exchange of information across its modules related to construction contracts, project cost estimates and daily work reports. In addition, the Trns•port data model includes additional con- tent that could serve as the basis for XML schema in the con- struction business area. S E C T I O N 3 Current Practice Review

14 Schema/Standard (Links) Content Developer/ Participants Screening Results LandXML www.LandXML.org Focus is the exchange of civil design information, including raw and reduced surveying data, surface data, parcel data, and 3D road model. Includes standard format for official electronic design submission. Most recent version incorporates mechanisms for interoperability with the Federal Highway Administration (FHWA) Interactive Highway Safety Design Model (IHSDM). Includes content of AASHTOWare SDMS. Derived from earlier ASCII-based Engineering and Surveying-Exchange (EAS-E) initiative. Schema is supported by over a dozen commercial applications Detailed evaluation Geographic Markup Language – GML http://www.opengeospatial.o rg/specs/ A comprehensive XML schema for encoding both spatial and nonspatial geographic information. Feature-centric model, defining abstractions of real-world phenomenon (e.g., roads) with properties having names, values, and types. Includes Rules for Application Schemas. Open Geospatial Consortium (OGC) Detailed evaluation XGDF XML http://www.iso.ch/iso/en/ CatalogueDetailPage.Catalogu eDetail?CSNUMBER=30763 The ISO TC204 (ITS) GDF standard supports location-based services, with a current focus on car navigation systems. Data model includes features (e.g., roadway, structures, and railways), relationships between features, and attributes of features or relationships. Includes roadway features, other transport modes, area features. Focus of attributes is on navigation needs. The next version of GDF is being called XGDF. Work has begun on adding both an SQL and XML encoding. ISO TC204 (Intelligent Transportation Systems) Detailed evaluation Geospatial One-Stop http://www.geo-one- stop.gov/Standards/ index.html As part of the National Spatial Data Infrastructure, the Geospatial One-Stop (GOS) data content standard formalizes how geographic information in any of seven themes can be represented for transfer between government agencies. The transportation theme includes modes of road, rail, transit, air, and navigable water. It is their intent to submit this specification to ANSI for standardization. The road mode of the transportation theme is consistent with constructs found in GDF. It includes the ISO 19133 linear referencing clause. An implementation specification based on OGC GML is anticipated. Federal Geographic Data Committee. Modeling teams had representatives from government, industry, and academia. The U.S. Department of Transportation Bureau of Transportation Statistics led the transportation theme model development. Detailed evaluation ISO 19133 http://www.iso.ch/iso/en/st dsdevelopment/techprog/ workprog/TechnicalProgram meProjectDetailPage.Technical ProgrammeProjectDetail?csnu mber=32551 Linear Referencing data standard. Provides a standard, generalized content format for specifying a location, applicable to most any linear referencing method. International Organization for Standardization (ISO) Technical Committee TC211 (Geographic information/Geomatics) Detailed evaluation Table 2. XML schema and data standards efforts.

15 Schema/Standard (Links) Content Developer/ Participants Screening Results aecXML – common object schema http://www.iai-na.org Architecture, engineering, and construction industry schema. Provides a content format for specifying building, plant, infrastructure, and facility information. aecXML aecXML Infrastructure Project (unpublished) Infrastructure project schema. Provides a content format for specifying infrastructure projects. aecXML AASHTOWare Trns•port XML Schema exists for construction contracts, project cost estimates, and daily work reports. Trns•port includes a broader construction management data model from which additional schema could be generated. Specific evaluations were completed for: • Bid subcontract commitment; • Construction project and contract information; • Construction contractor employee payroll submission format; • Construction project payment item cost estimates; • Construction project daily work report; • Construction project payment financial format; • Construction project proposal elements (including payment items); • Construction project proposal bid format; and • Construction project subcontract format. American Association of State Highway Transportation Officials (AASHTO) Detailed evaluation Detailed evaluation Detailed evaluation AASHTO BRIDGEWare No XML Schema, but standard data structures have been established that could provide a basis for a schema. Data domain for bridge design/rating (Virtis/Opis) covers superstructure description for common types of girder bridges. Work on substructure domain is in progress. Data model for bridge inspection, needs analysis and project planning is part of the Pontis portion of BRIDGEWare. American Association of State Highway and Transportation officials (AASHTO) Detailed evaluation NCHRP 12-50 XML standard http://www4.trb.org/trb/crp. nsf/All+Projects/ NCHRP+12- 50 Data structure (including an XML representation) for bridge analysis and rating. Includes specification information for steel gird er and pretensioned prestressed concrete girder type bridges. National Cooperative Highway Research Program (NCHRP) Detailed evaluation Table 2. (Continued). (continued on next page)

16 Schema/Standard (Links) Content Developer/ Participants Screening Results NCHRP 20-7, Task 149 SteelBridge XML (proposed) http://www4.nas.edu/trb/ crp.nsf/All+Projects/ NCHRP+20-07#149 The data model provided in the appendix of this report starts with the AASHTO Virtis/Opis data model and adds on specific classes related to fabrication and construction of steel bridges. National Cooperative Highway Research Program (NCHRP) Detailed evaluation American Institute of Steel Construction (AISC) CIS/2 http://www.aisc.org/ Standard for steel construction data exchange across CAD and analysis programs. This standard was referenced in the draft final report for NCHRP 20-7, Task 149. Since this standard is related more to buildings than transportation, a detailed review was not conducted. American Institute of Steel Construction (AISC) Reference American Iron and Steel Institute XML standard http://xml.coverpages.org/ aisi.html Effort to develop standardized XML terminology to be used throughout steel- related transactions documents. Because there appears to be limited recent development of the guidelines for this workgroup and it does not appear to be implemented a full evaluation was not conducted. Workgroups at the AISI web site Reference Reference Global JusticeXML http://it.ojp.gov/jxdm/ 3.0/index.html Comprehensive schema and data dictionary for data exchange among justice and public safety communities. Includes incident reports, driver histories, arrest warrants. U.S. Department of Justice Office of Justice Programs (OJP), Global Justice Information Sharing Initiative (GLOBAL), Georgia Tech Research Institute (GTRI) Detailed evaluation AASHTOWare – TSIMS http://tsims.aashtoware.org/ ContentManagement/ PageBody.asp?PAGE_ID=3&T AB_ID=4 http://tsims.aashtoware.org/ ContentManagement/ PageBody.asp?PAGE_ID=5&T AB_ID=8 The Transportation Safety Information Management System (TSIMS) is a proposed AASHTO project, and AASHTO will be proposing the use of XML in the upcoming solicitation release as the primary data exchange interface between all subsystems. The goal of TSIMS is to develop a uniform approach to management of traffic safety information. Guidelines are being developed, so that any vendor or agency can interface existing systems with it. The Object Broker at the core of the TSIMS will use XML for data interchange with outside systems. The entire TSIMS data dictionary will also be XML- compliant. (Please note: As of the time NCHRP 20-64 was completed, the TSIMS project had been discontinued. It is expected that this project will be replaced by a new, reduced scope project entitled “Safety Management System.”) AASHTO/FHWA Table 2. (Continued).

17 Schema/Standard (Links) Content Developer/ Participants Screening Results FMCSA http://cvisn.fmcsa.dot.gov/ Documents/ Document_Nav_Frame_Page_ documents.shtml http://infosys.fmcsa.dot.gov/ provu.asp In the area of transportation safety, the Federal Motor Carrier Safety Administration (FMCSA) has adopted XML as the standard data format for moving data between applications. Specific XML applications include Query Central, the Motor Carrier Profile report, the Inspection Selection System (ISS) data refresh, the Safety Audit upload process, and an interagency data exchange to automate driver/vehicle/carrier clearance along the border. FMCSA Crash Records Markup Language (CRML) XML tags for crash records information. University of Florida Transportation Research Center Detailed evaluation Detailed evaluation FARS ftp://ftp.nhtsa.dot.gov/ FARS/FARS-DOC National fatal accident reporting system – coding manual published with all data elements. NHTSA FRA http://safetydata.fra.dot.gov/ officeofsafety/Downloads/ Default.asp Standard reporting data formats for railroad accidents/incidents. FRA Traffic Model Markup Language – TMML http://www.ce.ufl.edu/trc/ research/tmml.htm TMML is a mechanism to share data among traffic modeling software products. Envisioned as an XML-compatible language prescribing class structure and data element tag names required to represent traffic model data, and create output data in format easily rendered by office productivity software. A limitation of TMML is that data must be specified in a separate Traffic Software Data Dictionary (TSDD), which serves as the source for the vocabulary and tags identifying classes and attributes. McTrans has adopted TMML for all of the HCS software modules. University of Florida Transportation Research Center Reference Reference Reference Reference Reference SAE ATIS http://www.sae.org/ The SAE Advanced Traveler Information Systems (ATIS) standards committee is developing an eXtensible Markup Language (XML) vocabulary for traveler information exchange. This work builds on the existing data dictionary (SAE J2353), message sets (SAE J2354 and J2369) and other related standards work. SAE Traffic Management Data Dictionary (TMDD) http://www.ite.org/tmdd/ index.asp Traffic Management Center-to-Center Communications data dictionary and messages – includes XML schema representation. AASHTO/ITE Table 2. (Continued). (continued on next page)

18 Schema/Standard (Links) Content Developer/ Participants Screening Results Traffic Software Data Dictionary (TSDD) http://www.tfhrc.gov/its/ its3.htm#traffic http://www.signalsystems. org.vt.edu/documents/Attach/ Leonard_tsddtsom.pdf Traffic engineering vocabulary, with many terms and definitions from the Highway Capacity Manual, FHWA documents, and CORSIM manuals. The TSDD is documented in P1489 format and was developed in parallel with the TMDD. An associated effort, the Traffic Software Object Model (TSOM), contains Unified Modeling Language (UML) object model diagrams that describe object classes, their attributes, and their relationships in the traffic simulation domain. FHWA-funded effort Reference IEEE P1512 http://www.standards.its.dot. gov/fact_sheetp.asp?f=12 Common Incident Management Message Sets for Use by Emergency Management Centers. IEEE SCC 32 ITS Incident Management Working Group Reference Reference UTDF – Universal Traffic Data Format http://www.trafficware.com Data exchange between signal controller systems and other software. TrafficWare National Transportation Communications for ITS Protocol (NTCIP) Standards Family of communications standards for message and data transfer between ITS control devices. Includes standards for “Center to Center” communications (e.g., between weather monitoring systems and freeway management systems), and “Center to Field” communications (e.g., between a traffic management center and individual signal controllers). AASHTO/ITE/ NEMA Reference Reference Reference COSMOS/PEER-LL Geotechnical Data XML Schema http://geoinfo.usc.edu/gvdc http://dmrl.usc.edu/pubs/sci 2003-web.pdf XML schema for geotechnical information. Consortium of Organizations for Strong Motion Observation Systems (COSMOS) Detailed evaluation Highway Performance Monitoring System (HPMS) http://www.fhwa.dot.gov/ohi m/hpmsmanl/hpms.htm Standard reporting format for highway performance information – reported annually by all state DOTs to FHWA. FHWA NCHRP 20-57 http://www4.nationalacademi es.org/trb/crp.nsf/All+Project s/NCHRP+20-57 This project developed generic tools to support asset management, along with a draft XML schema for the transportation asset performance tradeoff domain. NCHRP Table 2. (Continued).

Bridge The AASHTO BRIDGEWare data model addresses the Analysis and Design, Rating, Inspection, Management, and Maintenance topic areas in the Bridge Structures area and could serve as the basis for development of XML schemas in the bridge area. NCHRP 12-50 included development of an XML representation of a data structure for bridge analysis and rating; NCHRP 20-7 Task 149 addresses the bridge con- struction area—it included a proposed XML standard for steel bridges based on the Virtis/Opis data model. This stan- dard referenced an American Institute of Steel Construction standard (CIS/2) for exchange of steel construction data across CAD and analysis programs. Another related effort, still in its early stages, is ongoing at the American Iron and Steel Institute. Safety The topic areas listed in Table 1 for the safety area have been addressed to some extent by a number of different efforts. Important standards and guidelines related to trans- portation safety crash reports include ANSI D16 (Classifica- tion of Motor Vehicle Traffic Accidents), ANSI D20 (Data Element Dictionary for Traffic Records Systems), the Model Minimum Uniform Crash Criteria (MMUCC), and standard reporting formats defined by NHTSA for the Fatal Accident Reporting System (FARS), and by the Federal Railroad Admin- istration (FRA) for its Railroad Accident/Incident Reporting System. There are several XML efforts related to transportation safety that are related to the scope of TransXML as follows: • The Global JusticeXML effort provides XML schema rele- vant to transportation safety, with an emphasis on Cita- tions, Driver Information (arrest warrants, and driver his- tory) aspects of safety (as opposed to traffic analysis and crash reporting aspects). • NHTSA developed MMUCC XML as a subset of the Global JusticeXML Data Model (GJXDM)—this XML schema was released late in the TransXML project and therefore was not included in the Task 3 literature review. • The Traffic and Criminal Software package (TraCS) devel- oped by the State of Iowa in partnership with FHWA includes the MMUCC data elements and an XML data export routine. • The Federal Motor Carrier Safety Administration (FMCSA) uses XML as a standard data transfer format, addressing the Federal Motor Carrier topic area within the Safety business area. • A portion of the LandXML schema addresses Roadway Information for safety analysis—it is being used in con- junction with FHWA’s Integrated Highway Safety Design Model (IHSDM), to bring in grade information needed for roadway design safety analysis. • The AASHTOWare TSIMS effort produced a preliminary draft data dictionary with roadway characteristics relevant to traffic safety analysis. The TSIMS functional design envi- sions extensive use of XML as the means of data exchange across the different modules of that system. • The IEEE 1512 family of standards cover incident manage- ment, traffic management, and hazardous materials inci- dent response. • The COMCARE Alliance and the Emergency Interoper- ability Consortium have produced several XML data standards related to emergency response, including the Common Alerting Protocol (CAP), the Emergency Data Exchange Language (EDXL), and Vehicular Emergency Data Sets (VEDS). 19 Schema/Standard (Links) Content Developer/ Participants Screening Results Logistics XML/TransXML http://www.openapplications. org/wg/LogisticsXML.htm http://xml.coverpages.org/ tranXML.html XML standard for e-commerce activities of shippers and carriers. Open Applications Group (OAGi) Reference RecML – Recreation One-Stop XML http://www.xml.gov/ presentations/itpioneers/ RecML_files/frame.htm XML specification that defines terms for recreation areas (parks), facilities (trails, campgrounds, etc.), activities (hiking, wildlife viewing, etc.), alerts (temporary closures), events, and similar recreation elements. Recreation One-Stop Initiative Not directly related to TransXML Table 2. (Continued).

Other Relevant Efforts XML efforts that are related to the safety area but are cross-cutting in nature were also reviewed. These reviews are summarized below. Spatial Information Standards. Three standards bodies, ISO TC211 (GIS), OGC, and ISO/IEC SC32 JTC1, have developed standards for representing spatial information, much of which has relevance for the Safety business area (Crash Location). TC211’s 19107 Spatial Schema is a com- prehensive specification for a robust set of abstract geometry and topology types. OGC has selected a subset of geometry types (e.g., points, polylines, polygons), referred to as simple feature geometries. Their specification addressed implemen- tations based upon CORBA, SQL, and later Java. The JTC1 standard (SQL/MM Part 3 Spatial, 13249 3) covers an SQL’99 object relational implementation of simple feature geome- tries plus circular and compound curves and curve poly- gons. Though initially independent efforts, the three groups decided to harmonize their standards based upon a common geometry object model. This model is now supported by most of the major GIS vendors. Topology standardization is less mature. TC211 addresses topology at an abstract level. An effort to expand OGC simple feature geometries to include topology failed, though GML has been extended to include topology. Location Referencing Standards. At least three stan- dards currently are under development for standardizing the manner by which a location can be specified, which is of rel- evance for the Crash Location topic of the Safety business area. The farthest along is within the ISO TC211 19133 Location-Based Services, Tracking, and Navigation. The ITS Location Referencing Message Specification (LRMS) has just been reissued for comment as SAE J2266. WG 3.3 of ISO TC204 (ITS) has been struggling with achieving consensus in their location referencing standard, due to disparities in loca- tion referencing in America, Europe, and Asia. Roadway Information Standards. At least two stan- dards address roadway information, which is of relevance to the Roadway Inventory, Incident Management, Work Zone Safety, and Emergency Evacuation topics within the Safety business area. The ISO TC204 (ITS) Geographic Data Files (GDF) 14825 standard evolved from its European CEN coun- terpart. It specifies how roadways are represented for the in- car navigation systems market and is supported by roadway map vendors, such as Navigation Technologies and TeleAtlas. As part of the National Spatial Data Infrastructure, the Geospatial One-Stop (GOS) data content standard formalizes how geographic information in any of seven themes can be represented for transfer between government agencies. The transportation theme includes modes of road, rail, transit, air, and navigable water. It is their intent to submit this specifica- tion to ANSI for standardization. The road mode of the trans- portation theme is consistent with constructs found in GDF. It includes the ISO 19133 linear referencing clause. An imple- mentation specification based on OGC GML is anticipated. Traffic/ITS Standards. There have been several efforts to establish data standards in the area of traffic management and ITS. The Traffic Management Data Dictionary (TMDD) defines the specific data elements exchanged between Advanced Traffic Management System (ATMS) and other ITS applica- tions, such as Advanced Public Transit Systems, Advanced Traveler Information Systems (ATIS), and Commercial Vehi- cle Operations. Its goal is to provide nationally accepted def- initions to consolidate, resolve, and facilitate data exchange. Similar to TMDD, the P1512 Incident Management Data Dictionary defines data elements for information generated and transmitted between the emergency management sub- system to all other subsystems and providers. The ATIS Data Dictionary, developed by the Society of Automotive Engineers (SAE), contains a minimum set of medium-independent mes- sages and data elements needed to deploy ATIS services, and provide the basis for future interoperability of ATIS devices. The TSDD was developed in parallel with the TMDD, and standardizes data used by traffic analysis software. Finally, the Universal Traffic Data Format (UTDF) establishes a standard data format for signal and traffic-related data at intersections. 3.2 Screening and Evaluation of Schema and Standards The XML schema and data standards reviewed in Section 3.1 were screened to determine which should be evaluated in detail for potential incorporation in TransXML. The screen- ing criteria applied were as follows: • Relevant to the surface transportation business focus areas of bridge structures, safety, survey/design, and construction/ materials; • Beneficial to address a real business need and support data exchange across disparate applications for transportation planning, design, construction, maintenance and opera- tions; and • Nonproprietary namely, in the public domain. Table 2 indicates which schema and standards were selected for detailed evaluation. The detailed evaluations were designed to assess the suitability of the schema or stan- dard for inclusion in TransXML. Evaluation criteria were as follows: 20

• Extensible—Reusable elements; • Technically sound—Well-formed, well-structured, simple/ clean design, use of elements as opposed to attributes; • Practical—As demonstrated by the level of existing use, level of support from users and vendors, documentation, existence of sample schema and programs using those schema, ease of creating instance documents, ease of pars- ing; and • Compatible—With related data and XML standards that have been adopted by the user community—e.g., a schema with a crash type element should use compatible coding with existing ANSI standards for traffic data records. The detailed evaluations of the schema/standards are included in Appendix A. 21