FGDC-STD-014.7c-2008

Geographic Information Framework Data Content 

Standard 

Part 7c: Transportation - Roads 

May 2008 
ii

Federal Geographic Data Committee 

Established by Office of Management and Budget Circular A-16, the Federal Geographic Data 

Committee (FGDC) promotes the coordinated development, use, sharing, and dissemination of 

geographic data. 

The FGDC is composed of representatives from the Departments of Agriculture, Commerce, 

Defense, Education, Energy, Health and Human Services, Homeland Security, Housing and 

Urban Development, the Interior, Justice, Labor, State, and Transportation, the Treasury, and 

Veteran Affairs; the Environmental Protection Agency; the Federal Communications Commission; 

the General Services Administration; the Library of Congress; the National Aeronautics and 

Space Administration; the National Archives and Records Administration; the National Science 

Foundation; the Nuclear Regulatory Commission; the Office of Personnel Management; the Small 

Business Administration; the Smithsonian Institution; the Social Security Administration; the 

Tennessee Valley Authority; and the U.S. Agency for International Development. Additional 

Federal agencies participate on FGDC subcommittees and working groups. The Department of 

the Interior chairs the committee. 

FGDC subcommittees work on issues related to data categories coordinated under the circular. 

Subcommittees establish and implement standards for data content, quality, and transfer; 

encourage the exchange of information and the transfer of data; and organize the collection of 

geographic data to reduce duplication of effort. Working groups are established for issues that 

transcend data categories. 

For more information about the committee, or to be added to the committee's newsletter mailing 

list, please contact: 

Federal Geographic Data Committee Secretariat 

c/o U.S. Geological Survey 

590 National Center 

Reston, Virginia 22092 

Facsimile: (703) 648-5755 

Internet (electronic mail): fgdc@usgs.gov 

 World Wide Web: http://www.fgdc.gov
Federal Geographic Data Committee FGDC-STD-014.7c-2008 

Geographic Information Framework Data Content Standard 

Part 7c: Transportation - Roads

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Contents 

Introduction................................................................................................................................... vi

1 Scope........................................................................................................................................... 1

2 Conformance............................................................................................................................... 2

3 Normative references................................................................................................................. 2

4 Maintenance authority ............................................................................................................... 2

4.1 Level of responsibility...................................................................................................... 2

4.2 Contact information ......................................................................................................... 2

5 Terms and definitions ................................................................................................................ 2

6 Symbols, abbreviated terms, and notations............................................................................ 3

7 Road system model.................................................................................................................... 3

7.1 Road system ..................................................................................................................... 3

7.2 Road segmentation model............................................................................................... 4

7.2.1 Introduction....................................................................................................................... 4

7.2.2 RoadPoint.......................................................................................................................... 5

7.2.3 Anchor point ..................................................................................................................... 5

7.2.4 RoadSeg ............................................................................................................................ 5

7.2.5 Road segment equivalence ............................................................................................. 6

7.2.6 Anchor section ................................................................................................................. 6

7.2.7 RoadPath........................................................................................................................... 6

7.2.8 Attributes for road system............................................................................................... 7

7.3 The event model ............................................................................................................. 11

7.3.1 Introduction..................................................................................................................... 11

7.3.2 RoadAttributeEvent........................................................................................................ 11

7.3.3 RoadFeatureEvent.......................................................................................................... 12

7.3.4 RoadAttributeEvent data dictionary ............................................................................. 15

7.4 Code lists......................................................................................................................... 17

7.4.1 RoadLinearEventType code list.................................................................................... 18

7.4.2 RoadPointEventType code list...................................................................................... 21

Annex A (informative) Road example........................................................................................ 22

Annex B (informative) Bibliography .......................................................................................... 29

Figures 

Figure 1 – Relationship of road features to Transportation Base (Part 7) model................... 4

Figure 2 – RoadPoints bounding a RoadSeg (A, B) and non-RoadPoints (C, D).................... 5

Figure 3 – Road segment equivalence ........................................................................................ 6

Figure 4 – RoadAttributeEvent model ....................................................................................... 11

Figure 5 – RoadFeatureEvent model ......................................................................................... 13

Figure 6 – RoadPointEventType and RoadLinearEventType code lists................................ 17

Figure A.1 – Road example......................................................................................................... 22

Figure A.2 – Road points and road segments.......................................................................... 22

Figure A.3 – Approximate GIS linestring geometry ................................................................. 23

Figure A.4 – More precise engineering curve geometry ......................................................... 23

Figure A.5 – Road paths ............................................................................................................. 24
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Figure A.6 – Routes with milepoint values ............................................................................... 25

Figure A.7 – Speed limit road linear attribute events .............................................................. 26

Figure A.8 – Road segment point events.................................................................................. 27

Tables 

Table 1 – Data dictionary for road system.................................................................................. 7

Table 2 – Data dictionary for RoadAttributeEvent ................................................................... 15

Table 3 – CodeList for RoadLinearEventType.......................................................................... 18

Table 4 – CodeList for RoadPointEventType............................................................................ 21

Table A.1 – Road path to road segment mappings.................................................................. 25

Table A.2 – Road path speed limit linear attribute events ...................................................... 26

Table A.3 – Road segment speed limit linear attribute events ............................................... 27
Federal Geographic Data Committee FGDC-STD-014.7c-2008 

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Part 7c: Transportation - Roads

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Foreword 

Geographic information, also known as geospatial information, both underlies and is the subject 

of much of the political, economic, environmental, and security activities of the United States. In 

recognition of this, the United States Office of Management and Budget issued Circular A-16 

(revised 2002), which established the Federal Geographic Data Committee (FGDC) as a 

coordinating organization. 

Work on this standard started under the Geospatial One-Stop e-Government initiative. The 

standard was developed with the support of the member agencies and organizations of the 

FGDC and aids in fulfilling a primary objective of the National Spatial Data Infrastructure (NSDI), 

that is, creation of common geographic base data for seven critical data themes. The seven core 

data themes are considered framework data of critical importance to the geographic data 

infrastructure. 

As the Geographic Information Framework Data Content Standard was developed using public 

funds, the U.S. Government will be free to publish and distribute its contents to the public, as 

provided through the Freedom of Information Act (FOIA), Part 5 United States Code, Section 552, 

as amended by Public Law No. 104-231, “Electronic Freedom of Information Act Amendments of 

1996”. 
Federal Geographic Data Committee FGDC-STD-014.7c-2008 

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Introduction 

The primary purpose of this part of the Geographic Information Framework Data Content 

Standard is to support the exchange of road transportation data. This part seeks to establish a 

common baseline for the semantic content of road transportation databases for public agencies 

and private enterprises. It also seeks to decrease the costs and simplify the exchange of road 

transportation data among local, Tribal, State, and Federal users and producers. That, in turn, 

discourages duplicative data collection. Benefits of adopting this part of the standard also include 

the long-term improvement of the geospatial road transportation data within the community, 

improved integration of safety, emergency response, and enforcement data, and streamlined 

maintenance procedures. 

This part of the Framework Data Content Standard was preceded in development by the FGDC 

NSDI Framework Transportation Identification Standard and the National Cooperative Highway 

Research Program (NCHRP) 20-27(2). 
Federal Geographic Data Committee FGDC-STD-014.7c-2008 

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1 Scope 

The Geographic Information Framework Data Content Standard, Part 7c: Roads defines the 

components of a model for describing roads which, along with Air (Part 7a), Rail (Part 7b), Transit 

(Part 7d), and Inland Waterways (Part 7e), is one of five modes that compose the Transportation 

theme of the digital geospatial data framework. The primary purpose of this part of the standard 

is to support the exchange of transportation data related to road systems. It is the intent of the 

Roads part to develop a consensus around a set of common definitions for real world features in 

order to advance the goals of the NSDI. It is the intent of the part to set a common baseline that 

will foster the widest possible set of applications of road data for both user and producer. It is 

also intended to foster improvements in the common spatial data infrastructure through enhanced 

data sharing and the reduction of redundant data production. 

There are a number of issues common to the transportation domain that are covered in the 

Transportation Base (Part 7) part of the standard because of their broader applications. Some of 

these issues and their relevance for the Roads part are discussed in Annex A of the 

Transportation Base. 

At a high level, the road model described in the standard is made up of features that can have 

geographic locations and characteristics. These features can be interconnected in various ways 

to represent road networks for path finding/routing applications. While the design team has 

considered the need for path finding applications, the level of data required by such applications 

is beyond the scope of many organizations. Specifically, many State and local government 

agencies do not have adequate data for routing purposes and they do not have the budget to 

create and maintain this data. It is expected that the content in the Roads part will support the 

development of specialized networks for routing applications, but this level of information is not a 

requirement. 

This part of the Framework Data Content Standard can be implemented using a variety of 

software packages and is designed to accommodate data with or without geometry. While this 

document touches on implementation issues, it is not intended to serve as an implementation 

specification. It is designed to accommodate data associated with the complete road system at 

all levels of service and all functional classes that may be defined by a data-providing agency. It 

also accommodates assets associated with roads that are typically used for navigation, safety, 

and measurement. 

The Roads part of the standard applies to NSDI framework transportation data produced or 

disseminated by or for the Federal Government. According to Executive Order 12906, 

Coordinating Geographic Data Acquisition and Access: The National Spatial Data Infrastructure, 

Federal agencies collecting or producing geospatial data, either directly or indirectly (for example, 

through grants, partnerships, or contracts with other entities), shall ensure, prior to obligating 

funds for such activities, that data will be collected in a manner that meets all relevant standards 

adopted through the Federal Geographic Data Committee (FGDC) process. 

The Roads part relies extensively on ISO 19133 for linear referencing. Linear reference systems 

(LRS) are, in the strictest sense, not central to this part of the standard and also are complex 

enough to warrant separate treatment. Users should refer to Annex B of the Transportation Base 

(Part 7) part of the standard for information on linear reference systems. The use of LRS is not 

added simply to support the requirements of departments of transportation; LRS is used as a 

technique to transfer road information between systems in a simple, flexible data structure that 

does not impose a specific segmentation scheme on the data being exchanged. LRS is used in 

this part of the standard to support the exchange of asset information such as sign locations and 

pavement condition, as well as to support the placement of transportation statistics such as traffic 

counts or accident data along the roads, or the number of lanes, or speed limits. 

A linkage between this part of the standard and appropriate ISO standards for representing 

spatial features using the Unified Modeling Language (UML) has been developed. These upperlevel classes are not necessarily unique to roads, or even to transportation. A specific road 
Federal Geographic Data Committee FGDC-STD-014.7c-2008 

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2

profile of those standards has been assembled as the base classes for this model, primarily to 

take advantage of geometry, topology, and metadata standards. Additional work by ISO TC211 

and TC204 to harmonize Geographic Data Files (GDF) and linear referencing standards is in 

progress in parallel with the development of this standard. Annex B in the Base Document (Part 

0) contains a brief explanation of UML diagrams. 

2 Conformance 

This thematic part includes a data dictionary/model based on the conceptual schema presented 

below. To conform to this part, the user shall satisfy the requirements of the data 

dictionary/model. The user's conforming dataset shall include a value for each mandatory 

element and a value for each conditional element for which the condition is true. It may contain 

values for any optional element. The data type of each value shall be that specified for the 

element in the data dictionary/model and the value shall lie within the specified domain. This part 

only specifies the special requirements of conformance for a dataset containing information on 

the road system. Conformance to this part requires additional actions specified in the Base 

Document (Part 0) and Transportation Base (Part 7). 

3 Normative references 

Annex A of the Base Document (Part 0) lists normative references applicable to two or more parts 

of the standard, including those other than the transportation parts. No additional normative 

references are specified in the Transportation Base (Part 7). Informative references applicable to 

the Roads part only are listed in Annex B. Informative references applicable to two or more 

transportation parts only are listed in Annex C of the Transportation Base. Annex D of the Base 

Document lists informative references applicable to two or more of the parts, including those 

other than the transportation parts. 

4 Maintenance authority 

4.1 Level of responsibility 

The FGDC is the responsible organization for coordinating work on all parts of the Geographic 

Information Framework Data Content Standard. The United States Department of Transportation 

(USDOT), working with the FGDC, is the responsible organization for coordinating work on the 

Geographic Information Framework Data Content Standard, Part 7: Transportation Base and 

subparts (Parts 7a, 7b, 7c, and 7d, excluding 7e) and is directly responsible for development and 

maintenance of the transportation parts (excluding 7e) of the Framework Data Content Standard. 

4.2 Contact information 

Address questions concerning this part of the standard to: 

Federal Geographic Data Committee Secretariat 

c/o U.S. Geological Survey 

590 National Center 

Reston, Virginia 20192 USA 

Telephone: (703) 648-5514 

Facsimile: (703) 648-5755 

Internet (electronic mail): gdc@fgdc.gov

WWW Home Page: http://fgdc.gov

5 Terms and definitions 

Definitions applicable to the Roads part are listed here. Other terms and definitions applicable to 

multiple transportation parts of the standard are listed in the Transportation Base (Part 7). More 

general terms and definitions can be found in the Base Document (Part 0) part of the standard. 

Users are advised to consult these documents for a complete set of definitions. 
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5.1 

anchor section 

section of road between two anchor points 

NOTE Anchor sections state the official surface length of a road segment [NCHRP 20-27(2)] 

5.2 

equivalence relationship (between road points) 

correlation used to indicate that a road point in one dataset is equivalent to (that is to say, has the 

same physical location as) one or more road points in another dataset 

5.3 

equivalence relationship (between road segments) 

correlation used to indicate that a road segment in one dataset is equivalent to (that is to say, 

represents the same part of the physical road system as) one or more, whole or partial, road 

segments in another dataset 

5.4 

road feature 

entity that constitutes the road system 

NOTE A road feature is any type of transportation feature that is part of the road system. It is a type of 

transportation feature. 

5.5 

road path 

ordered list of whole or partial sections of physical road (that is to say, road segments) 

EXAMPLE An administrative route, such as Interstate 95, or a delivery route. 

6 Symbols, abbreviated terms, and notations 

Symbols, abbreviations, and notations common to two or more transportation parts are listed in 

the Transportation Base (Part 7). Symbols, abbreviations, and notations applicable to multiple 

parts, including the transportation parts, are listed in the Base Document (Part (0). 

7 Road system model 

7.1 Road system 

The road system model describes the geographic locations, interconnectedness, and 

characteristics of the street and roads in the larger transportation system. The transportation 

system includes physical and non-physical components representing all modes of travel that 

allow the movement of goods, services, and people between locations. 

The road infrastructure is comprised of physical components of the entire transportation system, 

generally consisting of public ways with perhaps a number of carriageways that are possibly 

paved. 

The focus of this part of the standard is to define a way to encode segments, their start and end 

points, and their attributes, which may have different values associated with different parts of a 

segment. The model has three main components: 

• A road segmentation model, which defines the representation of the physical segments of 

the road network (road segments), their connectivity (road points), and their usage (road 

paths) 
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• An event model, which defines a method to model attributes that may have values that 

change from one part of a segment to another and to linearly locate features along road 

segments or paths 

• A linear reference model, which defines how locations are specified along linear features. 

Strictly speaking, the linear reference model is not a part of this model, but is referenced 

because of the part it plays in handling the attribution for road features. The linear 

reference model is described in full in Annex B of the Transportation Base 

7.2 Road segmentation model 

7.2.1 Introduction 

Figure 1 – Relationship of road features to Transportation Base (Part 7) model 

To ensure maximum utility in a variety of contexts, this road model does not prescribe any 

specific business rules for the segmentation of the road system. The road network is the set of 

road features and their topological relationships which together define all possible movements 

through the road system. The road network can be broken up into segments called RoadSegs. 

RoadSegs represent individual pieces of the physical road network, such as that part of Main 

Street which exists between First Avenue and Second Avenue. It is highly recommended that 

RoadSegs be topologically connected by RoadPoints. RoadPoints serve to connect two 

RoadSegs. RoadPaths prescribe a usage of part of the road network, such as Route 66 or 

Washington Avenue. They represent a path through a set of whole or partial RoadSegs. 

RoadSeg, RoadPoint, and RoadPath are specializations of the transportation feature classes 

TranSeg, TranPoint, and TranPath, respectively (see Figure 1). All other real world entities 

comprising the road system are represented as road features. 
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7.2.2 RoadPoint 

RoadPoint is the specified location of an endpoint of a RoadSeg. This relationship is illustrated in 

Figure 2, where two RoadPoints, A and B, bound a RoadSeg. Point C represents the location of 

some real world entity such as an intersection or a bridge somewhere along the RoadSeg. Point 

D represents the location of another entity along the RoadSeg, but offset a lateral distance to one 

side. Because C and D do not terminate or represent the topological connection between 

RoadSegs, they shall not be represented as RoadPoints. Instead, if they represent real world 

entities (with attributes), they shall be represented as road features. FeatureEvents can be used 

to define their location along and optionally offset from a RoadSeg. Alternatively, Points C and D 

can be represented as AttributeEvents if they represent attributes instead of entities, such as the 

start of a bridge. This is explained further in the event model section below. 

Figure 2 – RoadPoints bounding a RoadSeg (A, B) and non-RoadPoints (C, D) 

RoadPoints can have geometry of type GM_Point and topology attribute of type TP_Node. Both 

GM_Point and TP_Node are inherited from TranPoint and defined in ISO 19107. 

7.2.3 Anchor point 

An anchor point represents a physical location in the field that can be unambiguously described 

so that it can be clearly located in the real world using the point description. An anchor point is a 

link between the computer representation of the road system and the real world. An anchor point 

shall occur at the ends of an anchor section. There is no requirement to include anchor points in 

the dataset being transferred, so all RoadPoints are not necessarily anchor points. Figure 1 

shows that RoadPoint has a Boolean attribute (isAnchorPoint) indicating whether the point is 

considered an anchor point. 

7.2.4 RoadSeg 

RoadSeg represents a continuous nonbranching linear section of a road, which means that 

RoadSeg represents a road segment. RoadSeg is a specified directed path between two 

RoadPoints along a physical road that identifies a unique segment of that system. Each segment 

has an identifier, with points used to start and end segments. It is important to note here that a 

RoadSeg does not necessarily have to be an entire road. It could be a single lane or a 

carriageway. Furthermore, a segment is not defined as a line on a map, but as a segment of 

physical road, of which the beginning, end, and length are determined by transportation agencies 

based on their business needs. The agencies determine where the junctions of segments are 

placed. 

RoadSeg extends TranSeg and is depicted in Figure 1. Because it extends TranSeg, RoadSeg 

inherits all properties from TranSeg including optional geometry of type GM_Curve as defined in 

ISO 19107. According to ISO 19107, GM_Curve extends GM_OrientableCurve and therefore 

has direction. RoadSeg also can have a topology of type TP_DirectedEdge, as defined in ISO 

19107. The reason TP_DirectedEdge has been introduced is to facilitate the representation of 

feature topology through its combinatorial structures independent of its geometry. For example, 

in the implementation of this model, a data provider may choose to represent only the geometry 

A B

C

D

offset
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Part 7c: Transportation - Roads

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of a RoadSeg, which implies a direction inherited from GM_OrientableCurve. Another data 

provider may choose not to supply road feature geometry and only provide the orientation of the 

RoadSeg using its topology attribute. 

7.2.5 Road segment equivalence 

Different transportation agencies may define their segments differently. In Figure 3, one agency 

has defined segment 1-1 extending from A to B. Another agency can represent the same section 

of road using two road segments, 2-1 and 2-2, with road points “A” and “B” and a new point “D.” 

The equivalence relationship on the RoadSeg class provides the ability to indicate that a segment 

is equivalent to one or more other segments. For example, segments 2-1 and 2-2 are equivalent 

to segment 1-1. The concepts of equivalency are described in detail in Annex A of the 

Transportation Base. 

Figure 3 – Road segment equivalence 

7.2.6 Anchor section 

An anchor section represents a section of road between two known and recoverable locations, 

that is to say, anchor points. RoadSeg has a Boolean attribute indicating whether the segment is 

an anchor section. Anchor sections state the official length of a road segment. Anchor points say 

where the anchor section starts and ends. The function of anchor sections is to support the 

collection of data by providing an "all distances measured on this piece of road shall add up to 

this length" checksum. Figure 1 shows that RoadSeg has an attribute to indicate whether it is an 

anchor section. 

7.2.7 RoadPath 

Because it is a path through the physical road network, RoadPath shall be an ordered list of 

whole or partial RoadSegs it uses, which may or may not be contiguous. RoadPath extends 

TranPath as shown in Figure 1. An example of RoadPath is an Interstate highway such as 

Interstate 40. The geometry of RoadPath is GM_MultiCurve, to allow for discontinuities in the 

path. The topology of RoadPath is TP_Complex and routeNumber is a character string. 

1-1

2-1 2-2

A B

2-3

C

D
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7.2.8 Attributes for road system Listed below in Table 1 are the road system objects and their attributes. 

Table 1 – Data dictionary for road system 

Line Name/Role Name Definition Obligation/ Condition Maximum Occurrence Data Type 

1 RoadPath 

Linear, possibly discontinuous portion of the road system that may be a collection of RoadSeg instances 

<<Feature>> 

2 Framework::Feature::identifier Feature identifier for the RoadPath M 1 <<DataType>> Framework::Identifier 3 Framework::Feature::metadata 

Structured or unstructured metadata as defined by the community of practice 

O 1 CharacterString 

4 Framework::Feature::attribute Producer-defined attribute for inclusion in transfer O * <<DataType>> Framework::Extended Attribute 5 Transportation Base:: TranFeature::lastUpdateDate Timestamp indicating when the RoadPath object was last edited M 1 DateTime 6 Transportation Base:: TranPath::geometry Geometric representation of the instantiated RoadPath entity O * <<Type>> GM_MultiCurve 7 Transportation Base:: TranPath::topology Topological representation O * <<Type>> TP_Complex 8 Transportation Base:: TranPath::routeNumber Public RoadPath identifier M 1 CharacterString 9 Role name: segment Road segment feature used by the RoadPath M * <<Abstract>> TransportationBase:: TranSeg 
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Line Name/Role Name Definition Obligation/ Condition Maximum Occurrence Data Type 

10 Role name: from Source RoadPath in equivalency C/part of equivalency? * <<Feature>> TransportationBase:: TranPath 11 Role name: to Destination RoadPath in equivalency C/part of equivalency? * <<Feature>> TransportationBase:: TranPath 12 RoadPoint RoadSeg terminus (start, end) <<Feature>> 13 Framework::Feature::identifier Feature identifier for the RoadPoint M 1 <<DataType>> Framework::Identifier 14 Framework::Feature::metadata 

Structured or unstructured metadata as defined by the community of practice 

O 1 CharacterString 

15 Framework::Feature::attribute Producer-defined attribute for inclusion in transfer O * <<DataType>> Framework:: ExtendedAttribute 16 Transportation Base:: TranFeature::lastUpdateDate Timestamp indicating when the RoadPoint object was last edited. M 1 DateTime 17 Transportation Base:: TranFeature:geometry Geometric representation of the instantiated road point entity O * <<Type>> GM_Point 18 Transportation Base:: TranFeature:topology Topological representation O * <<Type>> TP_Node 19 isAnchorPoint Indicates whether RoadPoint is an anchor point M 1 Boolean 20 Role name: startedSegment Segment that starts at the road point C/RoadSeg starts at RoadPoint? * <<Abstract>> TransportationBase:: TransSeg 21 Role name: endedSegment Segment that ends at the road point C/RoadSeg ends at RoadPoint? * <<Abstract>> TransportationBase:: TransSeg 
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Line Name/Role Name Definition Obligation/ Condition Maximum Occurrence Data Type 

22 Role name: from Source RoadPoint in equivalency C/part of equivalency? * <<Feature>> TransportationBase:: TranPoint 23 Role name: to Destination RoadPoint in equivalency C/part of equivalency? * <<Feature>> TransportationBase:: TranPoint 24 RoadSeg Linear, continuous, non-branching portion of the road system <<Feature>> 25 Framework::Feature::identifier Feature identifier for the RoadSeg M 1 <<DataType>> Framework::Identifier 26 Framework::Feature::metadata 

Structured or unstructured metadata as defined by the community of practice 

O 1 CharacterString 

27 Framework::Feature::attribute Producer-defined attribute for inclusion in transfer O * <<DataType>> Framework:: ExtendedAttribute 28 Transportation Base:: TranFeature::lastUpdateDate Timestamp indicating when the RoadSeg object was last edited M 1 DateTime 29 Transportation Base:: TranSeg::status 

Status of segment entity; for example, proposed, under construction, open to traffic, abandoned, and so on 

M 1 CharacterString 

30 Transportation Base:: TranSeg::fieldMeasure 

Length of segment, as determined in the field; if isAnchorSection = True, then this is the official length of the segment for the LRS 

M 1 Measure 

31 Transportation Base:: TranSeg::length 

Length of the RoadSeg feature, which may differ from the field measured length due to differences in calculation 

M 1 Measure 
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Line Name/Role Name Definition Obligation/ Condition Maximum Occurrence Data Type 

32 Transportation Base:: TranSeg::geometry Geometric representation of the instantiated segment entity O * <<Type>> GM_Curve 33 Transportation Base:: TranSeg::topology Topological representation O * <<Type>> TP_DirectedEdge 34 isAnchorSection Indicates whether road segment is an anchor section M 1 Boolean 35 Role name: startPoint RoadPoint corresponding to segment start O 1 <<Feature>> TransportationBase:: TranPoint 36 Role name: endPoint RoadPoint corresponding to segment end O 1 <<Feature>> TransportationBase:: TranPoint 37 Role name: from Source RoadSeg in equivalence C/part of equivalency? * <<Abstract>> TransportationBase:: TranSeg 38 Role name: to Destination RoadSeg in equivalence C/part of equivalency? * <<Abstract>> TransportationBase:: TranSeg 
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7.3 The event model 

7.3.1 Introduction 

Transportation events are the mechanism by which attributes or entities can be linearly located 

along either a TranSeg or a TranPath linear feature. Refer to the transportation event model in 

the Transportation Base for a more detailed overview of the transportation event model. 

Transportation events can be either attribute events or feature events. Within the Roads part, 

events specific to the road system are supported as specializations of transportation attribute and 

feature events. 

7.3.2 RoadAttributeEvent 

If an attribute value of a linear feature has a single, constant value along the entire length of the 

feature (for example, status and fieldMeasure), the attribute exists at the feature (RoadSeg or 

RoadPath) level and it is sufficient to store this single value with the feature. If the value of the 

attribute can change along the length of the linear feature (for example, speed limit, number of 

lanes); the location where each change occurs must also be specified. To accomplish this, 

RoadAttributeEvents are used. 

cd Context Diagram: Road Attribute Ev ents

«DataType»

RoadLinearAttributeEv ent

+ endPosition: LR_PositionExpression

+ linearEventT ype: RoadLinearEventT ype

+ startPosition: LR_PositionExpression

«DataType»

RoadPointAttributeEv ent

+ atPosition: LR_PositionExpression

+ pointEventT ype: RoadPointEventT ype

«Abstract»

Transportation Base::TranEvent

+ source: CharacterString

«DataType»

RoadAttributeEv ent

+ attributeValue: CharacterString

«Abstract»

RoadEvent

«Union»

LocatingRoadFeature

+ path: RoadPath

+ segment: RoadSeg

+event

1..*

+locatingFeature

Figure 4 – RoadAttributeEvent model 
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Each RoadAttributeEvent specifies a particular value for an attribute of a linear feature along with 

the location along that feature for which the value applies. RoadAttributeEvents are subtyped into 

point and linear events. A RoadPointAttributeEvent event occurs at a single position along a 

RoadSeg or RoadPath. This position is called an “at” position. RoadLinearAttributeEvents apply 

to a length of the RoadSeg or RoadPath. This interval is defined by a “start” and an “end” 

position on the RoadSeg or RoadPath. The “at”, “start”, and “end” positions used to locate an 

event are specified using a linearly referenced position expression. This expression specifies the 

linear reference method used to perform the measurement, the linear feature (RoadSeg or 

RoadPath) being measured, the measurement along the feature, and optionally the measurement 

laterally offset to either side. See Annex B of the Transportation Base for more details. 

7.3.2.1 RoadLinearAttributeEvent 

RoadLinearAttributeEvents provide the means of specifying the value and location of a single 

segment or path attribute that may apply only to part of the segment or path. The value of the 

segment or path attribute is specified as the attributeValue, inherited from RoadAttributeEvent. 

The location interval along which the value applies is specified by a “start” and “end” position 

along the segment or path, using linearly referenced position expressions explained in Annex B of 

the Transportation Base. The name of the attribute is specified by the linearEvent attribute of 

RoadLinearAttributeEvent. A code list of RoadLinearEventType values is supplied (see Figure 6). 

An example of a RoadLinearAttributeEvent is the speed limit of a road. The 

RoadLinearEventType value is “speedRestriction”. An attributeValue of 55 MPH might apply for 

only part of the road segment, delineated by “start” and “end” positions along the road segment. 

RoadLinearAttributeEvents have no geometry of their own but instead inherit any geometry which 

may have been defined for the segment or path to which they apply. 

7.3.2.2 RoadPointAttributeEvent 

RoadPointAttributeEvent provides the means of specifying the value and location of a single 

segment or path attribute that has a particular value only at a single point along the segment or 

path. The value of the segment or path attribute is specified as the attributeValue, inherited from 

RoadAttributeEvent. The point location is specified by an “at” position along the segment or path, 

using a linearly referenced position expression explained in Annex B of the Transportation Base. 

The name of the attribute is specified by the pointEvent attribute of RoadPointAttributeEvent. A 

code list of RoadPointEventType values is supplied (see Figure 6). An example of a 

RoadPointAttributeEvent is a stop sign along a road. The RoadPointEventType value is “sign”. 

An attributeValue of “stop” specifies the type of sign. The sign is located at a position along the 

road segment. The position expression allows the sign to be located at a position laterally offset 

from the center of the road. If more information is needed about the sign, the sign shall instead 

be represented as a feature and then linearly located with a RoadPointFeatureEvent. 

RoadPointAttributeEvents can also be used to specify where something like a pedestrian cross 

walk crosses the segment or path. RoadPointAttributeEvents have a linear location along a 

segment or path but have no explicit geospatial coordinate location of their own. This can be 

obtained from any geometry which may have been defined for the segment or path to which the 

RoadPointAttributeEvent applies. 

7.3.3 RoadFeatureEvent 

Features can have attributes, each with a single, constant value. One of these attributes can be 

the geometry of the feature. For example, a street sign road feature can have a height attribute 

and a point geometry. This feature can also be linearly located along one or more RoadSegs or 

RoadPaths. Each such linear location is specified by a RoadFeatureEvent. The 

RoadFeatureEvent linearly locates any feature along a RoadSeg or RoadPath. 

RoadFeatureEvents are subtyped into RoadPointFeatureEvents and RoadLinearFeatureEvents. 

A RoadPointFeatureEvent occurs at a single position along a RoadSeg or RoadPath. This 

position is called an “at” position. RoadLinearFeatureEvents apply to a length of the RoadSeg or 
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RoadPath. This interval is defined by a “start” and an “end” position on the RoadSeg or 

RoadPath. The “at”, “start”, and “end” positions used to locate an event are specified using a 

linearly referenced position expression. This expression specifies the linear reference method 

used to perform the measurement, the linear feature (RoadSeg or RoadPath) being measured, 

the measurement along the feature, and optionally the measurement laterally offset to either side. 

See Annex B of the Transportation Base for more details. 

Figure 5 – RoadFeatureEvent model 

7.3.3.1 RoadLinearFeatureEvent 

A RoadLinearFeatureEvent provides the means of specifying a linear location for a feature as a 

length along a segment or path. All of the feature’s attributes, including optional geometry, are 

included with the feature. The RoadLinearFeatureEvent is only attributed with the linear location. 

There are no restrictions on the type of feature being located. The feature can be linear, like 

guardrail. Guardrail attributes, like date installed or manufacturer, are kept with the guardrail 

feature. The location where the guardrail begins along the roadway is kept with the 

RoadLinearFeatureEvent, specified as the “start” position; the location where the guardrail ends 

is specified by the “end” position. The “start” and “end” positions each use a linearly referenced 

position expression explained in Annex B of the Transportation Base. The guardrail feature may 

not have geometry of its own, but instead rely on the geometry of the locating segment or path. 

Features with area geometries, like a county, are also supported. In this case, the 

RoadLinearFeatureEvent depicts what part of the segment or path is in the county. 

7.3.3.2 RoadPointFeatureEvent 

A RoadPointFeatureEvent provides the means of specifying a linear location for a feature as a 

single point location along a segment or path. All of the feature’s attributes, including optional 

geometry, are included with the feature. The RoadPointFeatureEvent is only attributed with the 

linear location of the feature along a segment or path, specified by a single “at” position along the 

segment or path using a linearly referenced position expression explained in Annex B of the 

Transportation Base. There are no restrictions on the type of feature being located. The feature 

can have a point footprint, like a stop sign. Sign attributes, like date installed or height, are kept 
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with the sign feature. The sign feature may not have geometry of its own, but instead rely on the 

geometry of the locating segment or path. Features with linear geometries, like a county 

boundary, are also supported. In this case, the RoadPointFeatureEvent depicts where the 

segment or path crosses the county boundary (that is to say, where the county changes). 
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7.3.4 RoadAttributeEvent data dictionary Listed below in Table 2 are the RoadAttributeEvent objects and their associated attributes. 

Table 2 – Data dictionary for RoadAttributeEvent 

Line Name/Role Name Definition Obligation/ Condition Maximum Occurrence Data Type 

39 RoadEvent Mechanism for locating an attribute value or feature along a road <<Abstract>> 40 Transportation Base:: TranEvent::source Supplier of the event object M 1 CharacterString 41 Role name: locatingFeature Road feature to which event is referenced M 1 <<Union>> LocatingRoadFeature 42 RoadAttributeEvent Mechanism for locating an attribute value along a road <<DataType>> 43 attributeValue Value of the attribute at the specified location M 1 CharacterString 44 RoadLinearAttributeEvent Mechanism for locating an attribute value for an interval along a road <<DataType>> 45 startPosition Starting location along the road for the attribute value M 1 <<Type>> LR_PositionExpression 46 endPosition Ending location along the road for the attribute value M 1 <<Type>> LR_PositionExpression 47 linearEventType Name of the attribute M 1 <<CodeList>> RoadLinearEventType 48 RoadPointAttributeEvent Mechanism for locating an attribute value at a single point along a road <<DataType>> 49 atPosition Point location along the road at which the attribute value applies M 1 <<Type>> LR_PositionExpression 
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Line Name/Role Name Definition Obligation/ Condition Maximum Occurrence Data Type 

50 pointEvent Name of the attribute M 1 <<CodeList>> RoadPointEventType 51 RoadFeatureEvent Mechanism for locating a feature along a road <<Abstract>> 52 Role name: linearlyLocatedFeature Feature that is located along the road M 1 <<Feature>> Framework:: Feature 53 RoadLinearFeatureEvent Mechanism for locating a feature along an interval along a road <<DataType>> 54 startPosition Starting location along the road for the feature M 1 <<Type>> LR_PositionExpression 55 endPosition Ending location along the road for the feature M 1 <<Type>> LR_PositionExpression 56 RoadPointFeatureEvent Mechanism for locating a feature at a single point along a road <<DataType>> 57 atPosition Point location along the road at which the feature is located M 1 <<Type>> LR_PositionExpression 58 LocatingRoadFeature Road feature used to locate a road event <<Union>> 59 segment RoadSeg used to locate a road event C/if path is notspecified 1 RoadSeg 60 path RoadPath used to locate a road event C/if segment is not specified 1 RoadPath 61 Role name: event Road event located by the feature M * <<Abstract>> RoadEvent 
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7.4 Code lists 

Figure 6 – RoadPointEventType and RoadLinearEventType code lists 
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7.4.1 RoadLinearEventType code list 

RoadLinearEventType is a CodeList of values for the attribute linearEventType. 

Table 3 – CodeList for RoadLinearEventType 

Name Definition 

operationalStatus Status of a roadway or part of a roadway; for example, proposed, under 

construction, open to traffic, abandoned, and so on 

routeNumber 

The route number of a road element, ferry element or chainage referencing 

section. The ID-number of a particular route in a given road network as 

Attributed by a national, sub-national or international organization (for 

example, the numbering of the departmental roads in France or the Eroads in Europe) 

directionalPrefix 

A geographic direction which is part of the official/alternate street name or 

route number of a road element or address area boundary element and 

which precedes the official/alternate street name body, route number body, 

street type prefix, or route type prefix 

directionalSuffix 

A geographic direction which is part of the official/alternate street name or 

route number of a road element or address area boundary element and 

which succeeds the official/alternate street name body, route number 

body, street type prefix, or route type prefix 

ownership Whether a road element is publicly or privately owned 

addressInformation The essential components of a street address 

alternateName The name of a feature that has no official status but is used or known by 

the general public 

alternateNameBody The part of the alternate name which has, compared to the prefix, most 

identifying power 

alternateNameText (A part of) an alternate name 

alternateStreetName The name of a road element or address area which has no official status 

but is used or known by the general public 

alternateStreetNameBody The part of the alternate name which has, compared to the prefix, most 

identifying power 

alternateStreetNameText (A part of) an alternate street name 

averageVehicleSpeed The average speed of vehicles traveling along a road element 

directionOfTrafficFlow The direction(s) of traffic flow allowed on a road element or ferry element 

or chainage referencing section 

dividedRoadElement An indication of the presence of a physical or legal divider which separates 

opposing lanes of traffic 

divider Information about the existence of a physical or legal divider along a road 

element which is not expressed by the individual features 

dividerType Classification of the divider along the road element 

dividerWidth The width of the divider along the road element 
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Name Definition 

emergencyVehicleLane Indicates whether the associated road element has a separate emergency 

vehicle lane 

externalIdentifier A unique alphanumeric identifier ascribed to a particular feature 

firstHouseNumber The first house number along the road element or the address area 

boundary element 

formOfWay Certain aspects of the physical form that a road element takes. It is based 

on a number of certain physical and traffic properties 

frequencyOfATrafficConnection The time interval between two departures of a traffic connection 

functionalRoadClass A classification based on the importance of the role that the road element 

or ferry connection performs in the connectivity of the total road network 

houseNumberRange The set of house numbers that is related to one side of a particular road 

element or to a particular address area boundary element 

houseNumberStructure The type of house numbering method that is applied to one side of a 

particular Road Element or to a particular address area boundary element 

intermediateHouseNumber 

A house number along the road element or the address area boundary 

element, which is not the first or the last house number along that road or 

address area boundary element 

laneDependentValidity For which of the lanes of an associated road element the associated subattribute or relationship holds or does not hold 

lastHouseNumber The last house number along the road element or the address area 

boundary element 

lateralOffset An indication of the lateral position of a road furniture or structure feature 

maxHeightAllowed 

The maximum height limit of a vehicle that may use the road element, ferry 

connection or chainage referencing section. The limit is normally set by a 

physical obstruction such as a bridge or tunnel, or a legal restriction 

maxLengthAllowed The legal maximum length of a vehicle that may use the road element, 

ferry connection or chainage referencing section 

maxNumberOfLanes The maximum number of lanes existing on a road element 

maxTotalWeightAllowed The legal maximum total weight of a vehicle that may use the road 

element, ferry connection or chainage referencing section 

maxWeightPerAxleAllowed The legal maximum weight per axle of a vehicle that may use the road 

element, ferry connection or chainage referencing section 

maxWidthAllowed 

The maximum width limit of a vehicle that may use the road element, ferry 

connection or chainage referencing section. The limit is normally set by a 

physical obstruction such as a bridge or a legal restriction 

minNumberOfLanes The minimum number of lanes existing on a road element 

minNumberOfOccupents The minimum number of occupants of a vehicle which are required by 

traffic restriction 

mountainPass The existence, height and opening period of a road element which is 

considered as a mountain pass 

multiMediaAction A specification of what to do with the multi-media object 

multiMediaDescription A description of the multi-media object 
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Name Definition 

multiMediaFileAttachment A multi-media file containing multi-media objects “decorating” the 

associated feature 

multiMediaFileAttachmentContext The context of the multi-media file attached to the feature 

multiMediaFileAttachmentName Name of the multi-media file attached to the feature 

multiMediaFileAttachmentType The type of the multi-media file attached to the feature 

multiMediaTimeDomain A specification when to perform the action indicated in the associated subattribute multi media action 

nameComponent The specification of a portion of a name which has a specific meaning 

nameComponentLength The length of a name component 

nameComponentOffset The offset of a name that represents the beginning of a name component 

nameComponentType The type of a name component 

namePrefix 

A part of the official or alternate name not belonging to the official/alternate 

name body, usually indicating the type of object the name refers to and 

which comes prior to the official/alternate name body 

numberOfLanes The number of lanes existing on a road element or chainage referencing 

section 

openingPeriod The period in which the function of an associated feature is available to the 

public 

pavedRoadSurfaceType The type of surface a paved road element has 

pavementStatus An indication of improvement applied to a road surface 

postalCode The official code of a postal area as defined by the national postal 

organization 

removableBlockage The way in which a removable barrier is to be removed 

roadGradient The road gradient percentage value on the road element 

roadInclination The transverse gradient of a road element 

scenicValue Whether a road element is regarded as scenic or not 

slipRoadType The type of slip road 

specialRestriction Special legal restrictions placed upon the use of a particular road element 

speedRestriction The maximum speed limit allocated to a road element 

trafficFlow Information about the traffic flow on road elements or chainage referencing 

sections 

trafficFlowMeasure The traffic flow on road elements or chainage referencing sections, 

expressed for instance by number of vehicles per day 

trafficFlowMeasurementType Classification of traffic flow measurement on road elements or chainage 

referencing sections 

trafficFlowMeasurementUnit Time unit over which the traffic flow measurement is recorded 

trafficJamSensitivity Probability of a traffic jam on a road element 
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Name Definition 

travelTime The one-way travel time that a ferry connection takes to complete a 

journey 

validityDirection The direction for which the value defined in an associated sub-attribute 

attached at the line feature is valid 

validityPeriod The period, for which a value defined in an associated sub-attribute or 

relationship, is valid 

vehicleType The type of vehicle for which the information contained in an associated 

sub-attribute or relationship holds 

width The width of a road element or chainage referencing section, a lane or a 

road furniture or structure feature 

7.4.2 RoadPointEventType code list 

RoadPointEventType is a CodeList of values for the attribute pointEventType. 

Table 4 – CodeList for RoadPointEventType 

Name Definition 

pass Whether a road element is regarded as a mountain pass 

tollbooth Location where tolls are collected for the use of a transportation facility 

tollCharge Fee to be paid to travel on (a section of) a toll road 

maxElevation The height above sea level of the road at the crest of a hill or mountain 

pass 

sign A device at an identified location used to convey information to the reader 
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Annex A (informative): Road example

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Annex A 

(informative) 

Road example 

The map in Figure A.1 depicts a set of roads which are to be exchanged using this part of the 

standard. 

66 42

66

42

Figure A.1 – Road example 

The data supplier chooses to create a segmentation model based on splitting the physical roads 

at all intersection locations. Road points are defined at these intersection locations. These are 

represented by road points 1, 2, 3, and 4 in Figure A.2. Road segments represent the physical 

roads between these road points. Road segment 101 starts at road point 1 and ends at road 

point 2; 102 from 2 to 3; and 103 from 2 to 4. 

101

102

103

1

2

3

4

Figure A.2 – Road points and road segments 
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Annex A (informative): Road example

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The road segments are depicted as straight lines in Figure A.2 to highlight the fact that they are 

not geometric shapes; they merely represent the physical roadway. Any number of geometric 

shapes can be associated with each road segment to represent its physical shape and location at 

varying levels of precision. Figure A.3 shows an approximate, linestring geometry for the road 

segments which may be sufficient for GIS applications. Figure A.4 shows a more precise, curve 

geometry which might be used for engineering design and construction. 

0 5 10 15 20

101

102

103

2

3

4

0

5

10

15

1

Figure A.3 – Approximate GIS linestring geometry 

0 5 10 15 20

101

102

103

2

3

4

0

5

10

15

1

Figure A.4 – More precise engineering curve geometry 
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Annex A (informative): Road example

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Regardless of the associated geometry, each road segment is attributed with a length value for 

use in linearly referenced calculations. Additionally, each road segment has a field measure 

value equal to the actual length of the physical road in the field. 

The rationale for segmentation is up to the data provider. It would have been acceptable to have 

alternatively defined a single road segment, 100, between road points 1 and 3 in a different 

dataset. Road segment 100 could then be equivalenced to segments 101 and 102. Alternative 

road points could have been defined at locations other than intersections, if the segmentation 

strategy was something other than intersection to intersection. 

Road paths are used to represent a usage of the road segments, such as for administrative 

routes. In Figure A.5, U.S. Route 66 follows the physical road represented by road segments 101 

and 102. State Highway 42 also uses 101 but then makes a right turn and follows road segment 

103. 

101 102 103

42

42

66 66

Figure A.5 – Road paths 

Because Route 66 uses the entire road segments and because its direction of increasing mileage 

matches the direction of the underlying road segments, it is sufficient to define the association 

between Route 66 and road segments 101 and 102 as a simple list. 

Because a road path can use partial as well as whole road segments, a more sophisticated 

mapping may be used. One way to achieve this is to use linear referencing to define matching 

locations on the path and the participating segments. Table A.1 shows the road segment 

mappings for paths 66 and 42. Positions along the paths are expressed using a milepoint linear 

reference method, where locations are measured in miles from the start of the path (see Figure 

A.6). Positions along road segments are defined using a percentage linear reference method, 

where locations are expressed as a percentage of the length attribute of the road segment, in the 

direction from its start to end road points. 
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Annex A (informative): Road example

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Table A.1 – Road path to road segment mappings 

Road Path Milepoint Road Segment Percentage 

Route 66 52.0 101 0 

 64.6 101 100 

 64.6 102 0 

 75.0 102 100 

Highway 42 10.0 101 0 

 22.6 101 100 

 22.6 103 0 

 35.0 103 100 

42

66 66

42

101 102 103

10.0 22.6

35.0

52.0 64.6 75.0

Figure A.6 – Routes with milepoint values 

Attributes can be defined directly for segments and paths if they apply to the entire segment or 

path, respectively. Examples of these are road segment length and road path route number. 

Often, attributes can change value along the length of the segment or path. This is encoded as 

road attribute events. 

Speed limit is an example of the linear type of road attribute event; the speed limit can have 

different values at different locations along a road segment or road path (see Figure A.7). The 

speed limit attribute events can be defined against road paths using a milepoint linear reference 

method as in Table A.2. 
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Annex A (informative): Road example

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66 42

66

42

101

102

103

10.0 22.6

35.0

52.0 64.6 75.0

SPEED

LIMIT

55

SPEED

LIMIT

55

SPEED

LIMIT

45

SPEED

LIMIT

45

SPEED

LIMIT

45

Figure A.7 – Speed limit road linear attribute events 

Table A.2 – Road path speed limit linear attribute events 

Road Path Speed Limit Value From Position Milepoint To Position Milepoint 

Route 66 55 52.0 58.3 

 45 58.3 69.8 

 55 69.8 75.0 

Highway 42 55 10.0 16.3 

 45 16.3 35.0 

Alternatively, since speed limit is functionally dependent upon the road segment rather than the 

routes that use it, speed limit road attribute events could be defined against the underlying road 

segments as in Table A.3. This way, a speed limit value is defined once but then usable by all 

routes using the road segment. This normalized approach facilitates edits to speed limit values – 

there is only one occurrence to be edited. It also makes it possible to give roads without route 

designations a speed limit value(s). 
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Annex A (informative): Road example

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Table A.3 – Road segment speed limit linear attribute events 

Road Segment Speed Limit Value From Position Percentage To Position Percentage 

101 55 0 50 

 45 50 100 

102 45 0 50 

 55 50 100 

103 45 0 100 

Road attribute events may occur at a single point along the road. An example of this point type of 

road attribute event is “sign”. This event is characterized by the value of the attribute, in this case 

the type of sign, and an “at” position defining its linearly referenced location. For the stop sign in 

Figure A.8, the value is “stop” and the “at” position is {road segment 103, percentage/feet, 0.1, left 

curb, -5.0}. The position expression shown within the curly braces is, in accordance with ISO 

19133, comprised of the linear element being measured (road segment 103), the linear 

referencing method (percentage with offsets measured in feet), a distance of 0.1% along the 

length of road segment 103 in the direction from road point 2 to 4, an offset referent equal to “left 

curb”, and an offset distance of 5.0 feet to the left of, that is, from the back of the curb. 

101 102 103

R R

Figure A.8 – Road segment point events 

If more information needs to be exchanged about the stop sign, then it can be encoded with a 

point feature (rather than attribute) event. This event has the same at position as defined above. 

Instead of an attribute value, it has an association to a sign feature. This feature can have 
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Annex A (informative): Road example

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whatever attributes are appropriate, for example authority = “DOT”, identifier = 1073625, 

description = “stop sign”, last update date = 1992-1-9, installed date = 1991-7-11, height = 5’6”, 

and GM_Point = (12.01, 13.99). Notice that, as a feature, the stop sign can have its own 

geometry, independent of its linearly referenced location along road segment 103. 

Figure A.8 has additional point attribute or feature events, such as a pedestrian crosswalk or a 

railroad crossing. School zones and no parking areas would more likely be encoded as linear 

attribute or feature events. 
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Part 7c: Transportation – Roads 

Annex B (informative): Bibliography

29

Annex B 

(informative) 

Bibliography 

The following documents contain provisions that are relevant to this part of the Framework Data 

Content Standard. Informative references applicable to two or more transportation parts only are 

listed in Annex C of the Transportation Base (Part 7). Annex D of the Base Document (Part 0) 

lists informative references applicable to two or more of the parts of the standard, including the 

transportation parts. For dated references, only the edition cited applies. For undated 

references, the latest edition of the referenced document applies. 

ANSI and ISO standards may be purchased through the ANSI eStandards Store at 

http://webstore.ansi.org/ansidocstore/default.asp, accessed October 2006. 

Federal Geographic Data Committee, NSDI framework transportation identification standard, 

http://www.fgdc.gov/standards/projects/FGDC-standardsprojects/fr_trans_id/?searchterm=identification%20standard, accessed October 2006, 

(suspended)