Previous Chapter: Appendix A: Glossary
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Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.

APPENDIX B

Model Elements Taxonomy

The model elements taxonomy (Table B-1) can be used to create a Model Element Table (MET), which has multiple applications for documenting the quality management process on a model. Agencies can use Table B-1 to create, add to, or adjust element groups and elements. This table contains examples and is not comprehensive.

Table B-1. Model elements taxonomy.

Discipline Element Group Elements
Survey Cadastral Boundaries
Control Monuments
Easements
Legal Description
Construction Layout
Localizations
Machine Control
Topographic Geodetic Control
Existing Features
Terrain (or 3D Surfaces)
Roadway Active Transportation Pedestrian Facilities
Bicycle Facilities
Driveways Driveways
Edge Treatments Curb and Gutter
Safety Edge
Shoulders
Geometry Horizontal Alignments
Vertical Alignments
Superelevation
Other Baselines
Interchanges Diverge Areas
Merge Areas
Ramps
Overpasses/Underpasses
Pavement Base Course
Binder
Joints
Overbuild
Overlay
Structural Course
Wearing Surface
Roadside Appurtenances Cattle Grates
Fences
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Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Discipline Element Group Elements
Drainage Culverts Inlet Controls
Pipes
Outlet Controls
Box Culverts
Drains Concrete Pavement Subdrainage
Edge Drain
French Drain
Trench Drain
Underdrain
Cross Drain
Open Conveyances Ditches
Swales
Retention and Detention Systems Infiltration Trenches
Injection Wells
Outlet Controls
Ponds/Drain Basins
Underground Detention Systems
Storm Sewers Grates
Pipes
Structures
Erosion Prevention and Sediment Control Buffers Permanent Buffers
Temporary Buffers
Permanent Best Management Practices (BMPs) Amended Soils
Check Dams
Rain Gardens
Riprap
Plantings
Tree Pits
Waterbodies and Wetlands
Temporary BMPs Berms and Diversions
Erosion Prevention Devices
Sediment Control Devices
Sediment Traps
Geotech Earth Retaining Systems Earth Retaining Systems
Engineered Embankments Geofoam
Geosynthetic Reinforced Soil–Integrated Bridge System
Surcharge
Geofabrics Geofabrics
Geohazards Geohazards
Subsurface Exploration Borings
Geophysics
Strata Surfaces
Traffic Barrier Systems Cable Barriers
Concrete Barriers
Crash Cushions
Delineators
Guiderail
Walls
Intersections Bicycle Facilities
Level Crossings
Pedestrian Facilities
Roundabouts
Signalized Intersections
Stop-Controlled Intersections
Intelligent Transportation Systems Connected Vehicle Systems
Fleet Monitoring Systems
Message Systems
Signal Systems
Tolling Systems
Weather Monitoring Systems
Page 71
Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Discipline Element Group Elements
Lighting Conduit
Control Boxes
High Mast Lighting
Low Mast Lighting
Junction Boxes
Luminaries
Pavement Markings Colored Pavement
Linear Striping
Perpendicular Striping
Raised Pavement Markers
Stenciled Striping
Rumble Strips Centerline Rumble Strips
Perpendicular Rumble Strips
Shoulder Rumble Strips
Signs Double Post Signs
Overhead Signs
Single Post Signs
Temporary Traffic Control Temporary Traffic Control
Bridge Structures Approach Structure Approach Slabs
Sleeper Slabs
Superstructure Bearings
Curb
Deck
Deck Drain
Deck Joints
Haunch
Girder
Median
Parapet (Barrier)
Railing
Sidewalk
Sound Wall (Barrier)
Transverse Member
Substructure Abutment/End Bent
Architectural Feature
Drilled Shaft
Footings/Pile Cap/Drilled Shaft
Cap
Micropile
Pedestal/Riser
Pier/Bent
Pier Cap
Pier Column
Pier Wall (Crash Wall)
Pile
Seal Coat/Tremie Seal/Seal Slab
Shear Key
Wingwall/Stem Wall
Slope Protection
Structural Components Element Details Bent Plate
Bolt Assembly
Conduit
Drainage System
Feature
Field Splice
Fill Plate
Gusset
Shear Connector (Stud)
Splice Plate
Stiffener
Weld
Page 72
Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Discipline Element Group Elements
Reinforcement Accessories
Drill and Bond Chemical Adhesive
Anchor
Drill and Bond Dowel Bar
Post-Tensioning
Prestressing
Structural Component
Reinforcement
Transverse Reinforcement
Coatings Coatings
Common Buried Structures Common Buried Structures
Walls Retaining Walls
Noise Walls
Perimeter Walls
Other Structures Gantries
Masts
Sign Structures
Utilities Communications Cable
Fiber-Optic
Telephone
Electrical Overhead Electrical
Underground Electrical
Landscaping Sprinkler Systems Landscaping Sprinkler Systems
Oil and Gas Gas Pipelines
Oil Pipelines
Sanitary Sewer Combined Storm and Sanitary
Systems
Gravity Systems
Pressure Systems
Septic Systems
Water Water Connections
Water Mains
Rail Geometry Cant
Horizontal Alignments
Vertical Alignments
Platforms Platforms
Power Systems Catenary System
Third Rail
Rail Signals Rail Signals
Track Ballast
Cross-Tie
Railing
Subballast
Switches/Turnouts/Crossovers
Site Development Grading Embankment
Excavation
Stabilization
Landscaping Irrigation Systems
Plantings
Walkways
Street Furniture
Page 69
Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Page 69
Page 70
Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Page 70
Page 71
Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Page 71
Page 72
Suggested Citation: "Appendix B: Model Elements Taxonomy." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press. doi: 10.17226/29171.
Page 72
Next Chapter: Appendix C: Review Documentation Property Set
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