US 421
Carrying US 421 over LAKE FREEMAN
01.50 S US 24, Carroll, Indiana
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US 421 in Carroll, Indiana sits above 86% of rated Indiana bridges on inventory load rating (46 t), while its 2001 build year is earlier than 17% of Carroll's recorded-year cohort (161 bridges).
US 421 in Carroll, Indiana is rated Good in the FHWA's 2024 National Bridge Inventory. Built in 2001, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 7. The lowest applicable rating sets the federal condition category, so this Good result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure IN:032340
POST-2000 · STEEL · MULTI-SPAN · SUB-LED · ARTERIAL-ADT · HEAVY-LOAD · CAT-GOOD
- POST-2000 2000+
- STEEL Steel
- MULTI-SPAN 3 spans
- SUB-LED Substructure-led
- ARTERIAL-ADT Arterial ADT
- HEAVY-LOAD Heavy load
- CAT-GOOD Good
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: US 421
The US 421 bridge in Carroll, Indiana carries US 421 over LAKE FREEMAN. It was built in 2001, making it 25 years old today. The structure is built primarily of steel continuous and spans 3 sections, stretching 154.2 meters (506 feet) end to end. Daily traffic averages 7,061 vehicles, placing it in the moderately-trafficked tier of Indiana bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 8/9, superstructure at 8/9, substructure at 7/9. The weakest component sits in good condition. All reported major components score above the Poor range.
How US 421 compares
Age against the county: built in 2001, earlier than 27 of Carroll's 161 bridges with a recorded construction year (17%), against a county median build year of 1977. This is one of the newer structures in its county.
Live comparison across Indiana bridges with a recorded inventory load rating (19,495 rated).
US 421 vs every rated Indiana bridge
Inventory load rating (metric tons), FHWA NBI, this state
46 Top 14% higher than 86% of 19,495 bridges
rated Indiana bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Carroll inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 161 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 2001
- Material
- Steel Continuous
- Number of Spans
- 3
- Structure Length
- 154.2 m (506 ft)
- Deck Width
- 13.6 m (45 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 7,061 vehicles/day
- Structure Number
- 032340
Condition Analysis
- • The deck (driving surface) rates good at 8/9, with no significant deterioration on file.
- • The superstructure (beams and supports above the deck) is in good condition (8/9), showing no significant deterioration.
- • The substructure (piers and abutments) is in good condition (7/9), showing no significant deterioration.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether US 421 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 421 against other structures in Carroll and across Indiana. Indiana 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 421?
US 421 in Carroll, Indiana has a deck rating of 8/9, superstructure rating of 8/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is US 421 inspected?
US 421'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 7,061 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 421 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 421?
US 421 has an NBI inventory load rating of 45.7 metric tons.
Who is responsible for maintaining US 421?
US 421 is owned and maintained by State Highway Agency.
How old is US 421 and does age affect safety?
US 421 was built in 2001, making it 25 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.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.