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92.1 Overview The research statement for Project 20-64 identified four business areas within surface transportation as the initial focus for TransXML: roadway survey/design, construction/ materials, bridge structures, and transportation safety. The different elements of these business areas are shown in Table 1 (which appears in the preceding section). While these selec- tions cover only a subset of the surface transportation domain, they provided a representative cross section of transporta- tion facility life-cycle phases as well as transportation facility components. This section introduces the four business areas from the perspective of potential data exchange requirements. Then, it provides a high-level view of other areas of surface trans- portation that should be considered as part of future work on TransXML. 2.2 Roadway Survey/Design Roadway design information includes horizontal and verti- cal centerline alignments, other aspects of the roadway geom- etry such as cross section, subsurface, and superelevation; and information about ancillary components such as pavement, shoulders, curbs, sidewalk, drainage pipes, and structures. There are three important sets of data exchange require- ments for roadway survey/design: information sharing among different members of a design team; information sharing between the road surveyor and designer; and finally, informa- tion transfer from design into the construction phase. Information about the roadway alignment from roadway designers needs to be shared with numerous other disciplines, such as bridge engineers, right-of-way specialists, drainage experts, soils engineers, traffic operations, and traffic safety analysts. This communication begins during preliminary design as the alignment first begins to take shape and pro- gresses as the detailed design evolves until a final design is approved. Thus, design data needs to be exchanged across multiple software tools that support individual specialties on a repetitive basis. These needs include exchange of informa- tion between geographic information systems and CAD tools. A two-way data exchange between the surveyor and designer is required. The surveyor provides the designer with informa- tion about the existing characteristics of the construction site. Once the design is complete, the designer provides the surveyor with information required for construction stake out. On completion of the design, there is a need to communi- cate information about the design to the prospective construc- tion team. The project can be viewed as a set of components or construction items, each with a requisite amount of relevant information to be tracked and communicated. The compo- nent items determined for bidding during the design phase transition into the components required for tracking con- struction progress and payment during the construction phase. Quantity takeoff, estimating, and specifications represent data exchange opportunities in preparation for bidding and contracting. In addition, geometric descriptions used in engi- neering calculations during design provide the basis for stake out calculations during construction. 2.3 Transportation Construction/Materials Data in the transportation construction/materials area includes both physical and business representations of a con- struction project. The physical view incorporates plans and specifications created in the design process and adds more specific information on materials placement and testing. The business view overlays information needed to bid, schedule, monitor, inspect, and manage the work. As noted above, there are significant opportunities for effi- ciency improvements by automating transfer of information from design into the construction phase. Use of surface mod- els produced in design for grading equipment machine control S E C T I O N 2 Surface Transportation Data Exchange Needs
is an example of thisâwhere considerable cost savings are already being achieved. Other data exchange needs during the construction phase include support for electronic bidding processes; transfer of bidding information into contractor payment systems; transfer of work tracking and payment information between central and field offices; transfer of materials testing infor- mation among the construction site, laboratories, and cen- tral offices; and information sharing about construction project status. 2.4 Highway Bridge Structures This business area spans bridge planning, design and analy- sis, construction, inspection, management, operations, and maintenance. Thus, bridge data includes information required for initial design of the structure, information about the phys- ical design of the structure as a whole and its individual ele- ments, information about the loads carried by the structure, condition and load rating information required for mainte- nance and permitting, and information about the function of the structure in the road network. Key data exchange processes in the bridge structures area include transfer of highway geometry parameters from high- way design to bridge design; transfer of bridge design infor- mation to highway engineers; provision of coordinates and station information to surveyors; loading of bridge design inputs (geometry, materials, loading information) to multi- ple design software packages; transfer of design information (geometry, quantities, digital terrain model information) to estimating systems; transfer of as-built information to inspec- tion, rating bridge management and maintenance manage- ment systems; and transfer of bridge design and inspection/ condition information to permitting and routing systems. Federal reporting of bridge inventory and inspection infor- mation represents another data exchange need. 2.5 Transportation Safety Transportation safety data includes information about crashes that occur (where, when, why, who, how), informa- tion about their consequences (emergency medical informa- tion, insurance information) and information about the characteristics of facilities, vehicles and drivers that pose safety risks. This latter set of data includes highway design and operational characteristics, vehicle registration infor- mation, vehicle inspection information, motor carrier inspec- tion and driving records, and citations. Raw crash report data is linked to roadway, vehicle, motor carrier, and driver information to yield additional informationâfor example, highway crash rates used for analysis of the need for safety projects are derived from crash reports and traffic data linked by location. Crash data need to be transferred from the collection point (e.g., a police report) to processing point(s) (for validation and linkage with other data) and then on to archive point(s). This process commonly involves exchange of the data across multi- ple agencies. Once processed, crash reports and linked crash information are shared across a wide variety of audiences (pub- lic agencies at state and local levels, interest groups, insurance companies, etc.). Given consistent key information required for linking across safety data sets, different types of safety data can be gathered from their respective sources and joined together for a variety of reporting and analysis purposes. Linkage of transportation safety-related information depends to a large extent on location identification. Unfor- tunately, different data sources typically use different location referencing methods and different roadway system models. Emerging software standards in these areas may provide a common understanding and representation scheme for XML encoding. Transportation safety has a significant real-time component as well, including activities such as roadside inspection of com- mercial vehicles, emergency response, incident management, driver information, and work zone management to ensure safety of road users. These activities rely on exchange of real- time data on traffic, incidents, response status, road conditions, and weather. These types of data exchange requirements are encompassed within the ITS area (see below). 2.6 Broader Framework for TransXML The four business areas selected for initial focus of TransXML cover an important, but relatively small portion of the universe of surface transportation data exchange needs. A broader framework for TransXML is illustrated in Figure 1. The first row in this diagram shows the initial four business areas; the second row shows potential future business areas. The final row of the figure shows areas where there are already active XML and standards development efforts that TransXML should link to or coordinate with. The broader framework for TransXML includes the fol- lowing distinct but overlapping viewpoints: Geospatial ViewâTransportation data is fundamentally geographic in nature, and therefore there has been consid- erable work to date on development of data standards and models focused on the geospatial representation of trans- portation information. These allow for sharing, linking, and integrating a variety of geographic data sets (including those from nontransportation domains). For example, the 10
Geospatial One-Stop (GOS) data content specification defines a standard representation of data related to road, rail, and transit modes. Feature models have also been developed by GIS vendors that can be used to develop geo- databases providing enterprise maintenance of and access to geographic data in support of multiple applications. The Open Geospatial consortium (OGC) is supporting contin- ued development of Geographic Markup Language (GML), which provides an abstract model for representing geo- graphic information. Infrastructure ViewâThis view is concerned with data exchange within and across different phases of the life cycle of planning, designing, constructing and maintaining trans- portation infrastructure. It incorporates planning, engineering/ design, and business perspectives and is the primary focus of the initial TransXML effort. However, this view goes beyond the four selected business areas, extending to activ- ities including planning and project development (environ- mental assessments, permits, right-of-way, etc.), program development/budgeting, asset management (inventory, inspec- tion, performance monitoring, life-cycle cost modeling, selec- tion and prioritization of treatments), and maintenance management (identifying, scheduling and managing main- tenance activities). A recent TRB paper (1) proposed a semantic architecture to represent the highway construc- tion domain using an integrated supply chain model, encom- passing planning, design, field construction, and maintenance. Elements of ebXML (2) are used for electronic business transactions related to highway construction. This paper can be revisited at a later date as TransXMLâs scope is broadened. Safety ViewâThis view (to be addressed in the initial TransXML effort) is concerned with collection, reporting, analysis and use of information needed to reduce transporta- tion crashes and fatalities. ITS/Operations ViewâThe National ITS Architecture (3) represents an important reference model for surface trans- portation processes and data flows. This Architecture defines functions and data flows for real-time operation and man- agement of the surface transportation system. It encompasses eight different âbundlesâ of user services: travel and traffic management, public transportation management, electronic payment, commercial vehicle operations, emergency man- agement, advanced vehicle safety systems, information man- agement (including archiving real time data for use in other applications), and maintenance and construction manage- ment. As data interoperability is a key objective of the ITS architecture effort, there are a number of active ongoing ITS data standards efforts, including NTCIP (National Trans- portation Communications for ITS Protocol), CVISN (Commercial Vehicle Information Systems and Networks), Archived Data, Incident Management, Traffic Management, ATIS (Advanced Traveler Information Systems), and TCIP (Transit Communications Interface Profile). XML data for- mats have or are being developed for several ITS-related areas, including motor carrier safety data, transportation management center to center communications and traveler information exchange. Travel and Traffic Modeling and Simulation ViewâThis view is concerned with exchange of data inputs and outputs of transportation modeling and simulation toolsâincluding 11 Operations/ ITS TransXML Modeling/ Simulation Geospatial Data Freight/ Logistics Asset Management Maintenance Management Project Development Program Development Survey/Design Construction/Materials Bridge Safety Figure 1. TransXML current and potential future scope.
socioeconomic data, traveler characteristics, network repre- sentations, and network characteristics (travel times and costs). The Traffic Software Data Dictionary (TSDD) pro- vides an example of data exchange needs from the traffic modeling point of view. A recent paper (4) reported develop- ment of TrafficXML to support exchange of data between simulation programs of different vendors. FHWAâs Next Generation Simulation Models (NGSIMS) effort is currently developing a data dictionary to support new microsimulation algorithms being developed under that project. Freight Logistics ViewâThis view is concerned with the intermodal freight supply chainâsharing of information on shipment and equipment status and location. The TransXML developed by Transentric covers this area; the standard is now being extended by the Open Applications Group. 12
