Digital Model–Based Project Development and Delivery: A Guide for Quality Management (2025)
Chapter: Appendix B: Model Elements Taxonomy
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Appendix A: Glossary
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 |
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 |
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 |
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 |
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