US 18 & 52
Carrying US 18 & 52 over NATURAL STREAM
0.6 MI. W OF E JCT. US 52, Clayton, Iowa
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: US 18 & 52
The US 18 & 52 bridge in Clayton, Iowa carries US 18 & 52 over NATURAL STREAM. It was built in 1967, making it 59 years old today. It was last reconstructed in 2023, extending its service life. The structure is built primarily of steel continuous and spans 4 sections, stretching 90.8 meters (298 feet) end to end. Daily traffic averages 3,780 vehicles, placing it in the moderately-trafficked tier of Iowa bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in good condition. All reported major components score above the Poor range. Its NBI inventory load rating is 32.1 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How US 18 & 52 compares
Live comparison across Iowa.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1967
- Last Reconstructed
- 2023
- Material
- Steel Continuous
- Number of Spans
- 4
- Structure Length
- 90.8 m (298 ft)
- Deck Width
- 10.8 m (35 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 3,780 vehicles/day
- Structure Number
- 000000000020480
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in good condition (7/9), showing no significant deterioration.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • The substructure (piers and abutments) rates good at 7/9, with no significant deterioration on file.
How to read this record
This page shows what the last federal inspection recorded, not whether US 18 & 52 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare US 18 & 52 against other structures in Clayton and across Iowa. Iowa bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for US 18 & 52?
US 18 & 52 in Clayton, Iowa has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is US 18 & 52 inspected?
US 18 & 52's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 3,780 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 18 & 52 is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for US 18 & 52?
US 18 & 52 has an NBI inventory load rating of 32.1 metric tons.
Who is responsible for maintaining US 18 & 52?
US 18 & 52 is owned and maintained by State Highway Agency.
How old is US 18 & 52 and does age affect safety?
US 18 & 52 was built in 1967, making it 59 years old and last reconstructed in 2023.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
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.