Tool · Decode
Bridge condition decoder
Enter the NBI component ratings from a bridge record to decode its current Good, Fair, or Poor condition category.
According to the Federal Highway Administration (FHWA), more than 575,000 public highway bridges are reported through the National Bridge Inventory. Current inspection intervals are risk-based; this decoder applies the federal condition thresholds to the component ratings you enter. For the full rubric and limitations, see our methodology.
How the NBI condition scale works
FHWA condition ratings use a 0–9 scale. The overall condition category comes from the lowest applicable deck, superstructure, substructure, or culvert rating: 7–9 is Good, 5–6 is Fair, and 0–4 is Poor. This tool accepts the three common bridge-component ratings; a culvert record should be checked against its culvert rating too.
“Structurally deficient” is a retired federal reporting term that still appears in older reports and news coverage. FHWA eliminated that status beginning with the 2018 archive and now reports the component-based result as Poor condition. FHWA also discontinued the calculated sufficiency-rating item; the optional value above is shown only as historical context and never changes the current condition result.
What does the decoder tell me?
Does Poor condition mean unsafe?
No. It is a condition category, not a live crossing decision. Only the bridge owner or transportation agency can post, restrict, or close a bridge.
Why does the worst element decide the category?
A bridge is only as sound as its weakest load-carrying component, so FHWA derives the overall condition from the lowest element rating rather than an average.
Explore more
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.