308TH AVE.
Carrying 308TH AVE. over SUGAR CREEK
083E40404, Clinton, Iowa
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: 308TH AVE.
The 308TH AVE. bridge in Clinton, Iowa carries 308TH AVE. over SUGAR CREEK. It was built in 1985, making it 41 years old today. The structure is built primarily of prestressed concrete and spans 1 section, stretching 14.9 meters (49 feet) end to end. Daily traffic averages 70 vehicles, placing it in the lower-traffic tier of Iowa bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 7/9, substructure at 4/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed. Its NBI inventory load rating is 36.0 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How 308TH AVE. 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 How the historical reference is calculated.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
- 1985
- Material
- Prestressed Concrete
- Number of Spans
- 1
- Structure Length
- 14.9 m (49 ft)
- Deck Width
- 6.1 m (20 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 70 vehicles/day
- Structure Number
- 000000000125251
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 7/9, the deck (driving surface) is in good shape and shows no significant wear.
- • The superstructure (beams and supports above the deck) rates good at 7/9, with no significant deterioration on file.
- • The substructure (piers and abutments) rates poor at 4/9, advanced deterioration that should be prioritized for repair.
How to read this record
308TH AVE. is in the federal Poor condition category. That is a component-based result, not a closure order.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
- Compare 308TH AVE. against other structures in Clinton 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 308TH AVE.?
308TH AVE. in Clinton, Iowa has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is 308TH AVE. inspected?
308TH AVE.'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 70 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 308TH AVE. is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for 308TH AVE.?
308TH AVE. has an NBI inventory load rating of 36.0 metric tons.
Who is responsible for maintaining 308TH AVE.?
308TH AVE. is owned and maintained by County Highway Agency.
How old is 308TH AVE. and does age affect safety?
308TH AVE. was built in 1985, making it 41 years old.
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.