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

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