US Bridges

US 18 over Lost Island Outlet

Fair

Clay County, Iowa · 1.0 Mi. E of Jct. SR M54 · Structure no. 000000000020360

Built
1931
94 years old, rebuilt 1965
Condition
Fair
inspected October 2024
Type
Slab
Concrete Continuous
Length
105 ft
3 main spans
Daily traffic
4,270
2022 count
Owner
State
State Highway Agency

About this bridge

US 18 over Lost Island Outlet is a concrete continuous slab carrying US 18 over Lost Island Outlet in Clay County, Iowa. It was built in 1931 and reconstructed in 1965, so it is 94 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 4,270 vehicles a day, roughly 16% of them trucks, projected to reach 4,270 by 2044. The structure is 105 ft (32 m) long and 36 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesUS 18
CrossesLost Island Outlet
Location1.0 Mi. E of Jct. SR M54
RouteU.S. Route 18
CountyClay County
StateIowa
Coordinates43.12682, -95.01426
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.9 US tons
Inventory rating26.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length105 ft (32 m)
Longest span40 ft (12.2 m)
Deck width36 ft (11 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,270 (2022)
Projected traffic4,270 by 2044
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 18 over Lost Island Outlet built?

It was built in 1931, making it 94 years old in 2025. It was reconstructed in 1965.

What condition is US 18 over Lost Island Outlet in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in October 2024.

How much traffic does US 18 over Lost Island Outlet carry?

About 4,270 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is US 18 over Lost Island Outlet?

The structure is 105 ft (32 m) long with a longest span of 40 ft (12.2 m) and a deck 36 ft wide.

Who owns US 18 over Lost Island Outlet?

It is owned by the State Highway Agency.