Bridge Trend Reports
Data-driven reports highlighting the biggest year-over-year movers in the FHWA National Bridge Inventory — bridges whose ratings declined, structures that were repaired, and state-level aggregate shifts. Updated each spring after the federal NBI release.
What These Reports Track
Every report on this page is generated from the FHWA National Bridge Inventory, the federal database of every public-road bridge longer than 20 feet in the United States. The NBI is compiled from biennial inspections that each state DOT submits under the National Bridge Inspection Standards. Each structure receives independent 0-to-9 ratings for deck, superstructure, and substructure, plus operational ratings for load capacity and waterway adequacy.
We diff the latest annual NBI submission against the prior year for every bridge in the inventory, then surface the largest absolute and proportional changes. Reports are grouped by report type so you can browse by what you care about: declines (condition fell), improvements (condition rose, often after rehabilitation), aggregates (state, county, and structure-type roll-ups), and snapshots (point-in-time portraits of a sub-population such as the busiest interstate spans).
Reports in This Release (2 total)
1 decline report · 0 improvement reports · 0 aggregate reports
States With the Most Structurally Deficient Bridges
Highest percentage of bridges rated as deficient
States With the Oldest Bridges
Where bridge infrastructure is most outdated
How to Read a Trend Report
Each report opens with a leaderboard of the entities driving that specific trend. For per-bridge declines, you will see the structures whose Condition Score dropped the most points year over year. For improvements, you will see structures whose ratings rose, typically following a deck overlay, beam replacement, or full rehabilitation project documented in the NBI work history fields. For aggregates, you will see counties or states ordered by total deficient deck area, percent of inventory rated Poor, or another roll-up depending on the report.
Below the leaderboard, each entity links through to its detail page where you can see the full rating history and the inspection trail. Year-over-year changes in NBI ratings are sometimes data-quality artifacts — a state DOT correcting a prior submission, a re-inspection after disagreement, or a reclassification from culvert to bridge. We do not attempt to filter those out at the trend level; the per-bridge view is where you should verify before drawing conclusions about a specific structure.
What These Reports Cannot Tell You
NBI ratings describe observed physical condition; they do not predict failure and they are not a posted weight limit. A bridge with a Poor superstructure rating may still be perfectly safe at posted loads, and a bridge with Good ratings can still develop scour or fatigue cracks between inspections. The U.S. Department of Transportation's Bureau of Transportation Statistics and the ASCE Infrastructure Report Card publish complementary national-level analysis if you are looking for a higher-level read on U.S. bridge condition.
For methodology — how we compute the Condition Score, how we identify year-over-year declines, and how we handle missing ratings — see the BridgeWatch methodology page.
Frequently Asked Questions
What do BridgeWatch trend reports track?
Each trend report compares the most recent year of FHWA National Bridge Inventory data against prior NBI submissions to surface meaningful year-over-year changes — bridges whose condition ratings dropped, bridges that were repaired or rehabilitated, and aggregate state and county-level shifts. Reports are regenerated whenever new NBI data is published, typically once per year. Last updated April 2026.
Where does the underlying data come from?
All trend reports use bridge condition ratings published by the Federal Highway Administration in the National Bridge Inventory (NBI). The NBI is a federal database compiled from inspections required of every state DOT under the National Bridge Inspection Standards (NBIS). Each bridge longer than 20 feet on a public road is inspected at least every 24 months, and the deck, superstructure, and substructure are each rated 0 to 9. We compute year-over-year deltas in those ratings to flag the largest movers.
What does it mean when a bridge "declined" in a report?
A decline means the bridge's NBI condition ratings fell since the prior year — for example, a deck rating moving from 6 (Satisfactory) to 4 (Poor). A decline does not by itself mean the bridge is unsafe or that closure is imminent. NBI ratings describe physical condition, and posted weight limits or closures are decisions made by the state DOT, not by the inventory itself. If you are concerned about a specific structure, the relevant state DOT and the FHWA bridge program are the authoritative sources.
How often is the trend data refreshed?
FHWA publishes a complete NBI bulk file annually, typically in the spring covering the prior calendar year of inspections. We regenerate trend reports within days of each new NBI release. Aggregate state-level reports use multi-year averages so that a single late submission from one state does not distort the picture.
How do these reports compare to the ASCE Infrastructure Report Card?
The American Society of Civil Engineers issues a national grade for U.S. bridges every four years as part of its Infrastructure Report Card. ASCE assigns a single letter grade and writes a narrative; BridgeWatch publishes the per-bridge condition data underlying that judgment, plus year-over-year movement at the structure, county, and state level. The two are complementary — ASCE provides the headline assessment, NBI provides the structural inventory.