US 18 over Big Sioux River
Fair Condition48 years old2,130 vehicles/day
Location
| State | Iowa |
| County | Lyon |
| Location | At S.dakota Border |
| Carries | US 18 |
| Crosses | Big Sioux River |
| Coordinates | 43.30718, -96.52828 |
Condition Ratings
| Overall Condition | Fair |
| Deck | 5 (Fair) |
| Superstructure | 6 (Satisfactory) |
| Substructure | 7 (Good) |
| Channel/Waterway | 7 (Good) |
| Scour Critical | 8 — Stable, low risk |
Physical Characteristics
| Material | Steel Continuous |
| Design | Stringer/Multi-beam |
| Total Length | 580.1 ft (176.8 m) |
| Max Span | 162.1 ft (49.4 m) |
| Deck Width | 46.6 ft (14.2 m) |
| Deck Area | 2510.6 sq m |
| Main Spans | 4 |
| Year Built | 1978 |
Traffic
| Avg Daily Traffic | 2,130 (2022) |
| Truck Traffic | 20% |
| Lanes On Bridge | 2 |
Inspection & Ownership
| Last Inspection | 324 |
| Inspection Frequency | Every 24 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Structure Number | 000000000034481 |