Editorial & Corrections Policy

PlainBridges publishes a condition page for every public highway bridge in the United States - across all 50 states, the territories, and more than 3,000 counties, built entirely from the Federal Highway Administration's National Bridge Inventory. This page explains how those pages are produced, what standards they are held to, and how to report a figure that looks wrong so we can fix it at the source.

How these pages are produced

Every condition rating, load rating, year-built, and traffic count on PlainBridges originates in the U.S. Federal Highway Administration (FHWA) National Bridge Inventory (NBI) - the federal database, mandated by Congress since 1968 after the Silver Bridge collapse, that records the condition of every public highway bridge in America. We download the annual NBI data files from the FHWA, load them through a documented, version-controlled data pipeline, and render them into bridge, county, and state pages using shared templates. No bridge page is hand-written, and no source rating is typed in by an editor. Derived Good/Fair/Poor categories, rollups, and comparisons are calculated from those source fields and labeled as PlainBridges derivations.

PlainBridges is responsible for the decisions a pipeline cannot make on its own: which datasets to use, how each field is defined and labeled, what the methodology says, how derived measures (such as a structural-deficiency rate or a state-versus-national comparison) are computed, which guides and explainers we write, and what we will not publish. The pipeline then applies those decisions uniformly across every bridge, so the rule that governs one page governs all of them. We do not claim, and you should not infer, that a person individually re-reads every generated bridge page before it is published, the integrity of those pages comes from the source data and the documented rules applied to it, not from manual review of each one.

Sourcing standards

We publish only data that comes from official government sources, and we name the source on every page. Our data is:

• FHWA National Bridge Inventory (NBI): the annual delimited-ASCII state files describing every public highway bridge over 20 feet, the source for every condition rating (deck, superstructure, substructure and culvert, each on the 0–9 NBI scale), inventory load rating, year built, structure material, span count, average daily traffic, and location shown across the site.
• FHWA NBI specifications: the 2024 archive follows the former Recording and Coding Guide; current reporting is governed by the Specifications for the National Bridge Inventory (SNBI). We distinguish the source vintage and specification rather than treating the older guide as current.

We do not scrape third-party bridge databases, we do not republish proprietary or crowd-sourced condition estimates, and we do not generate any bridge data ourselves. Where a figure is derived from the official data (for example, a state's Poor-condition rate or a percentile comparison), the page links to our methodology, which sets out exactly how it is calculated.

Accuracy and validation

Because the values are read straight from FHWA files, the most common limitation is the source itself rather than a transcription error. NBI condition ratings reflect the most recent inspection a state submitted, which can be up to 24 months old, and involve professional judgment that can vary between inspectors. Our pipeline applies systematic checks before a value is published: it classifies a bridge as Poor when the lowest applicable component rating is 4 or below, shows a value as unavailable when the source omits it rather than guessing, and reconciles county and state rollups against the underlying bridge records so the same figure is consistent wherever it appears.

When we find that a displayed number is wrong, we fix the cause, not the symptom. We trace the value back to the data layer, correct the derivation or labeling rule there, and regenerate the affected pages, so the same class of error is resolved everywhere at once rather than patched on a single page. (For example, when we found that the NBI inventory load rating was being mislabeled as a 0–100 sufficiency score, we corrected the label and the derivation at the source rather than on individual pages.)

Editorial independence

PlainBridges does not accept payment, sponsorship, or promoted placement from any contractor, operator, state agency, or organization in exchange for how a bridge is presented. Our only revenue source is contextual display advertising served by Journey by Mediavine. Advertisers have no influence over which bridges we cover, how a condition is reported, or how any page ranks. The figures are a transparent presentation of the official FHWA numbers, not an engineering assessment of whether a structure is safe to cross.

Update schedule

The FHWA publishes a new National Bridge Inventory dataset annually, typically in the spring covering the prior year's submissions. We refresh our database after each release and re-stamp the affected pages so the published date reflects when the data genuinely changed. Because inspections always lag the present, the source vintage named on each page, and explained in our methodology - is the primary tool for judging how current a figure is.

Corrections process

If a figure looks wrong, please tell us. We treat data-error reports as a priority and follow the same process every time:

1. Report. Email hello@plainbridges.com with the page URL and the figure you are questioning.
2. Verify. We check the value against the official NBI source record for that bridge, county, or state.
3. Fix at the source. If the figure is wrong on our side, we correct the underlying data or derivation rule and regenerate every page it affects.
4. Note it. If the figure is correct but reflects a known NBI limitation, an old inspection cycle, a missing field, or inspector subjectivity, we explain the caveat rather than silently changing it.

Some apparent errors trace back to the FHWA record itself. When that is the case, we will tell you so and, where possible, point you to the official FHWA National Bridge Inventory so you can verify it directly.

Our public data changelog records verified corrections and material methodology changes that we can corroborate from the source data or our own processing history.

Contact

Questions about our standards, methodology, or a specific figure are welcome at hello@plainbridges.com. For more on what the data covers and how it is processed, see our About page and methodology. For how to use this information responsibly, see our disclaimer.