National Bridge Inventory
 Part of United States mapping project.
|
_-_The_Noun_Project.svg){kind=small}
See Import/Guidelines and Automated Edits code of conduct for more information. Imports/automated edits which do not follow these guidelines might be reverted!
The National Bridge Inventory (NBI) is a dataset produced by the Federal Highway Administration (FHWA) containing information on public bridge and tunnel structures in the United States and overseas territories. Data is recorded by federal, state and tribal governments per national specifications[1], then compiled annually into a single dataset. Information is included on structure location, type, specifications, inspections and condition ratings.
More information on the program and its datasets are available here on the FHWA website.
Dataset
The NBI dataset is available for download in text format, with annual collections dating back to 1992. The data may be downloaded individually per state or as a single file.
The latest collection is also published as part of the National Transportation Atlas Database (NTAD) and may be downloaded in CSV, Excel, ESRI shapefile, GeoJSON formats, or accessed as a feature server through the REST API. This dataset is preprocessed and filtered for highway bridges only.[2]
NBI Coding Guide
The Coding Guide is the standard used to produce the currently available dataset[3]. First published in 1995, it defines the format of the database. Each record is a 445-byte ASCII sequence.[4]
Each structure (bridge, tunnel, culvert) is identified primarily by a FIPS PUB 5-2 state code and 15-character alphanumeric structure number provided by the state agency. Other identifying information includes geographic coordinates and names of the roads(s) and/or waterway(s) associated with the structure. More complex structures may consist of multiple records.[3]
Important Items
Note: data may be preprocessed or filtered for some sources like the NTAD, e.g. decoding text fields to decimal numbers, omitting fields, changing field names, etc.
| Item | Name | Description | Characters |
|---|---|---|---|
| 1 | State code | FIPS PUB 5-2 state code of the reporting agency | 3 |
| 8 | Structure number | 15-character alphanumeric number reported by the state; shouldn't change | 15 |
| 6A | Facility intersected | Description of way the structure intersects | 24 |
| 7 | Facility carried | Description of way the structure carries | 18 |
| 16 | Latitude | XX deg, XX min, XX.XX sec | 8 |
| 17 | Longitude | XXX deg, XX min, XX.XX sec | 9 |
| 20 | Toll | Indicates whether the structure and/or road is tolled | 1 |
| 27 | Year built | 4 | |
| 42 | Type of service | Type of service on (A) and under (B) the bridge | 2 |
| 43 | Structure type | Description of material (A) and design/construction type (B) of the main structure | 3 |
| 49 | Structure length | Length of way supported by structure in meters (XXXXX.X) | 6 |
| 52 | Deck width, out-to-out | Width of the structure in meters (XXX.X) as defined on p.30-31 of the coding guide[3] | 4 |
| 62 | Culverts | Numeric condition of culvert or "N" if structure not a culvert | 1 |
| 64 | Operating rating | Absolute maximum permissible load of vehicle in metric tons (XX.X) | 3 |
| 106 | Year reconstructed | Most recent year of major reconstruction | 4 |
Equivalent OSM Tags
In most cases it is necessary to carefully interpret the NBI data and either match with an existing OSM bridge or culvert, or create a new way in OSM.
| NBI Item | OSM Tag | Notes |
|---|---|---|
| 1 State code | Key:ref:US:NBI:state_code | Proposed |
| 8 Structure number | Key:ref:US:NBI:structure_number | Proposed |
| 20 Toll | Key:toll | Code "3" indicates toll-free |
| 27 Year built | Key:start date | |
| 43 Structure type | Key:bridge:structure | 43B design type "19" indicates a culvert (see item 62) |
| 62 Culverts | Tag:tunnel=culvert | If culvert condition specified, this is likely not a bridge or tunnel (use best judgement; see item 43) |
| 64 Operating rating | Key:maxweight | Not enough data to determine weight limits for different vehicle types; may exceed legal limits |
Verification
The following items don't have direct tagging in OSM, but may be useful for verification.
| NBI Item | Notes |
|---|---|
| 6A Facility intersected | May be useful for locating a bridge with inaccurate coordinates |
| 7 Facility carried | May be useful for locating a bridge with inaccurate coordinates |
| 16 Latitude | |
| 17 Longitude | |
| 42 Type of service | May be useful to verify types of ways on and under the structure |
| 49 Structure length | May be useful to verify mapped length (note: width in case of a culvert) |
| 52 Deck width, out-to-out | May be useful for Tag:man made=bridge objects (note: length in case of a culvert) |
Specifications for the National Bridge Inventory (SNBI)
The Specifications for the National Bridge Inventory (SNBI) is a new standard published in 2022 and expected to be fully implemented by 2028[5]. The SNBI contains improvements and revisions of the previous Coding Guide.
License
As defined by the US Constitution and as a work of the federal government, the dataset is free for public use.[2]
References
- ↑ US Department of Transportation, Federal Highway Administration. National Bridge Inspection Standards. https://www.fhwa.dot.gov/bridge/nbis.cfm
- ↑ 2.0 2.1 US Department of Transportation, Bureau of Transportation Statistics. National Transportation Atlas Database: National Bridge Inventory. https://hub.arcgis.com/datasets/usdot::national-bridge-inventory/about
- ↑ 3.0 3.1 3.2 US Department of Transportation, Federal Highway Administration. "Recording and Coding Guide for the Structure Inventory and Appraisal of the Nations Bridges". Published December 1995. https://www.fhwa.dot.gov/bridge/mtguide.pdf
- ↑ US Department of Transportation, Federal Highway Administration. NBI Record Format. https://www.fhwa.dot.gov/bridge/nbi/format.cfm
- ↑ US Department of Transportation, Federal Highway Administration. Memorandum "Action: Implementation of the Specifications for the National Bridge Inventory". Published May 25, 2022. https://rosap.ntl.bts.gov/view/dot/77620