LOC 170TH ST
Carrying LOC 170TH ST over SMALL STREAM
072310901, Union, Iowa
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
LOC 170TH ST in Union, Iowa sits above 92% of rated Iowa bridges on inventory load rating (48 t), while its 1988 build year is earlier than 40% of Union's recorded-year cohort (169 bridges).
LOC 170TH ST in Union, Iowa is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1988, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 4. The lowest applicable rating sets the federal condition category, so this Poor 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 IA:000000000326051
LATE-CENTURY · TIMBER · MULTI-SPAN · SUB-LED · LOCAL-ADT · HEAVY-LOAD · CAT-POOR
- LATE-CENTURY 1980–1999
- TIMBER Wood or timber
- MULTI-SPAN 2 spans
- SUB-LED Substructure-led
- LOCAL-ADT Local ADT
- HEAVY-LOAD Heavy load
- CAT-POOR Poor
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: LOC 170TH ST
The LOC 170TH ST bridge in Union, Iowa carries LOC 170TH ST over SMALL STREAM. It was built in 1988, making it 38 years old today. The structure is built primarily of wood or timber and spans 2 sections, stretching 12.2 meters (40 feet) end to end. Daily traffic averages 113 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 6/9, superstructure at 6/9, 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.
How LOC 170TH ST compares
Age against the county: built in 1988, earlier than 67 of Union's 169 bridges with a recorded construction year (40%), against a county median build year of 1980. This is one of the newer structures in its county.
Live comparison across Iowa bridges with a recorded inventory load rating (23,718 of 23,719 rated).
LOC 170TH ST vs every rated Iowa bridge
Inventory load rating (metric tons), FHWA NBI, this state
48 Top 8% higher than 92% of 23,718 bridges
rated Iowa 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.
Union inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 169 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
- 1988
- Material
- Wood or Timber
- Number of Spans
- 2
- Structure Length
- 12.2 m (40 ft)
- Deck Width
- 8.5 m (28 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 113 vehicles/day
- Structure Number
- 000000000326051
Condition Analysis
- • The deck (driving surface) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • The substructure (piers and abutments) is in poor condition (4/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
LOC 170TH ST 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 LOC 170TH ST against other structures in Union 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 LOC 170TH ST?
LOC 170TH ST in Union, Iowa has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is LOC 170TH ST inspected?
LOC 170TH ST'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 113 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. LOC 170TH ST 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 LOC 170TH ST?
LOC 170TH ST has an NBI inventory load rating of 48.2 metric tons.
Who is responsible for maintaining LOC 170TH ST?
LOC 170TH ST is owned and maintained by County Highway Agency.
How old is LOC 170TH ST and does age affect safety?
LOC 170TH ST was built in 1988, making it 38 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.