US 18 over Prairie Creek

Fair

Palo Alto County, Iowa · 2.8 MI W of W Jct. Ia 15 · Structure no. 000000000039180

Built: 1923; 102 years old, rebuilt 1958
Condition: Fair; inspected August 2023
Type: Slab; Concrete Continuous
Length: 63 ft; 2 main spans
Daily traffic: 2,510; 2022 count
Owner: State; State Highway Agency

About this bridge

US 18 over Prairie Creek is a concrete continuous slab carrying US 18 over Prairie Creek in Palo Alto County, Iowa. It was built in 1923 and reconstructed in 1958, so it is 102 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 2,510 vehicles a day, roughly 29% of them trucks, projected to reach 2,510 by 2043. The structure is 63 ft (19.2 m) long and 34 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesUS 18

CrossesPrairie Creek

Location2.8 MI W of W Jct. Ia 15

RouteU.S. Route 18

CountyPalo Alto County

StateIowa

Coordinates43.08295, -94.49824

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.

Component	Rating	Meaning
Deck	5 Fair	All primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure	5 Fair	All primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure	5 Fair	All primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection	7 Good	Some minor problems.

Last inspectionAugust 2023

Inspection intervalevery 24 months

Operating statusOpen, no restriction

ScourFoundations stable; scour within limits of footing or piles

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 adequacy6: Equal to present minimum criteria

Approach roadway alignment8: Equal to present desirable criteria

Operating rating44.6 US tons

Inventory rating26.8 US tons

Structure

Structure typeSlab

MaterialConcrete Continuous

DeckConcrete, cast-in-place

Main spans2

Design loadH 20

Structure length63 ft (19.2 m)

Longest span30 ft (9.1 m)

Deck width34 ft (10.5 m)

Roadway width30 ft (9.1 m)

Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,510 (2022)

Projected traffic2,510 by 2043

Trucks29%

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 statusPossibly eligible for the National Register; requires further investigation

Work proposedNone recorded

Estimated improvement cost—

NavigationNo navigation control on waterway

Frequently asked questions

When was US 18 over Prairie Creek built?

It was built in 1923, making it 102 years old in 2025. It was reconstructed in 1958.

What condition is US 18 over Prairie Creek 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 August 2023.

How much traffic does US 18 over Prairie Creek carry?

About 2,510 vehicles per day (2022 count), of which roughly 29% are trucks.

How long is US 18 over Prairie Creek?

The structure is 63 ft (19.2 m) long with a longest span of 30 ft (9.1 m) and a deck 34 ft wide.

Who owns US 18 over Prairie Creek?

It is owned by the State Highway Agency.