FM over Rock River
PoorLyon County, Iowa · 098463501 · Structure no. 000000000228960
- Built
- 1970
- 55 years old
- Condition
- Poor
- inspected July 2023
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 348 ft
- 4 main spans
- Daily traffic
- 399
- 2022 count
- Owner
- County
- County Highway Agency
About this bridge
FM over Rock River is a steel continuous stringer/multi-beam or girder carrying FM over Rock River in Lyon County, Iowa. It was built in 1970, so it is 55 years old, older than the Iowa average of 45.5 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 399 vehicles a day, roughly 29% of them trucks, projected to reach 399 by 2043. The structure is 348 ft (106.1 m) long and 30 ft wide. If it were closed, the detour would be 3.7 mi (6 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was FM over Rock River built?
It was built in 1970, making it 55 years old in 2025.
What condition is FM over Rock River in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in July 2023.
How much traffic does FM over Rock River carry?
About 399 vehicles per day (2022 count), of which roughly 29% are trucks.
How long is FM over Rock River?
The structure is 348 ft (106.1 m) long with a longest span of 98 ft (29.9 m) and a deck 30 ft wide.
Who owns FM over Rock River?
It is owned by the County Highway Agency.