About PlainBridges

Our Mission

PlainBridges exists because the structural health of America's bridges should be easy for every driver, commuter, and taxpayer to check, without navigating federal spreadsheets or paying for proprietary infrastructure databases.

We believe that bridge safety data collected at public expense belongs to the public in a form they can actually use. The Federal Highway Administration maintains the National Bridge Inventory with detailed condition data on every public highway bridge in America. PlainBridges makes this data searchable, browsable, and understandable for non-engineers.

Our goal is infrastructure transparency. When you cross a bridge every day, you should be able to check its condition rating, see when it was last inspected, and understand what its Good, Fair, or Poor condition category means.

Our Data Sources

Federal Highway Administration (FHWA) - National Bridge Inventory (NBI)

All bridge data on PlainBridges comes from the National Bridge Inventory, the federal database mandated by Congress since 1968 following the catastrophic Silver Bridge collapse in Point Pleasant, West Virginia. The NBI is the most comprehensive bridge condition database in the world, covering public highway bridges across the United States.

The NBI includes condition ratings (deck, superstructure, substructure on a 0-9 scale), year built, material type, span count, average daily traffic, and geographic coordinates for every public highway bridge.

Official source: FHWA National Bridge Inventory.

How We Process the Data

We download the annual NBI dataset from FHWA and process it as follows:

• Parsing: NBI data arrives as fixed-width text files with one file per state. We parse each record into structured fields following the FHWA Recording and Coding Guide.
• Condition classification: We apply FHWA's official classification thresholds to categorize bridges as Good, Fair, or Poor from the lowest applicable component condition rating.
• Geographic organization: Bridges are organized by state and county for browsable navigation, with coordinates for precise location reference.
• Statistics computation: We calculate state-level and county-level aggregations including Poor-condition shares, average age, condition distributions, and maintenance priority indicators.

Reported fields are preserved, while derived categories and rollups are labeled and documented. PlainBridges also recomputes the discontinued sufficiency rating only as a historical reference when its inputs are available.

Data Currency

PlainBridges currently displays the 2024 National Bridge Inventory data release. FHWA releases updated NBI data annually, typically in the spring covering the prior calendar year. Routine inspection intervals are risk-based under current NBIS rules; 24 months is common, with shorter or approved extended intervals for qualifying bridges.

Bridge condition can change between inspection cycles due to weather events, traffic loads, or maintenance work. The NBI reflects the most recent inspection data submitted by each state. We update PlainBridges when new annual data becomes available from FHWA.

Editorial Independence

Content on PlainBridges is compiled by PlainBridges. Raw data from the FHWA National Bridge Inventory is transformed into readable profiles, validated against the source before publication. PlainBridges is responsible for editorial standards, methodology, and corrections.

We do not accept payment, sponsorship, or promoted placement from manufacturers, operators, or any transportation/product entity. Our only revenue source is contextual display advertising served by Journey by Mediavine, advertisers do not influence which entities we cover or how we present data, and they do not receive preferential placement.

Limitations & Disclaimers

PlainBridges is an informational resource, not an engineering assessment tool:

• Not real-time: NBI data reflects the most recent inspection, which may be up to 24 months old. Current conditions may differ from what is shown.
• Poor condition is not a live safety decision: It means the lowest applicable component rating is 4 or below. FHWA retired “Structurally Deficient” as a reported status beginning with the 2018 archive.
• Inspection subjectivity: Condition ratings involve professional judgment and may vary between inspectors. A bridge rated 5 by one inspector might be rated 4 or 6 by another.

PlainBridges is not affiliated with FHWA, the U.S. Department of Transportation, or any government agency. We are an independent data portal presenting public information in a more accessible format. For safety concerns about a specific bridge, contact your state Department of Transportation.

Contact

Questions or feedback? Email hello@plainbridges.com.

PlainBridges is an independent data publisher. How our pages are produced, the standards they are held to, and how to report a correction are described in our editorial & corrections policy.