US 18 over Drainage Ditch

Fair

Palo Alto County, Iowa · 4.6 Mi. E of E Jct. Ia 4 · Structure no. 000000000039150

Built: 1958; 67 years old
Condition: Fair; inspected August 2023
Type: Slab; Concrete
Length: 26 ft; 1 main span
Daily traffic: 3,500; 2022 count
Owner: State; State Highway Agency

About this bridge

US 18 over Drainage Ditch is a concrete slab carrying US 18 over Drainage Ditch in Palo Alto County, Iowa. It was built in 1958, so it is 67 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 6 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 3,500 vehicles a day, roughly 21% of them trucks, projected to reach 3,500 by 2043. The structure is 26 ft (7.9 m) long and 34 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

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CarriesUS 18

CrossesDrainage Ditch

Location4.6 Mi. E of E Jct. Ia 4

RouteU.S. Route 18

CountyPalo Alto County

StateIowa

Coordinates43.11213, -94.58766

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	6 Satisfactory	Structural elements show some minor deterioration.
Superstructure	6 Satisfactory	Structural elements show some minor deterioration.
Substructure	6 Satisfactory	Structural elements show some minor deterioration.
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 evaluation6: Equal to present minimum criteria

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 rating57.4 US tons

Inventory rating34.7 US tons

Structure

Structure typeSlab

MaterialConcrete

DeckConcrete, cast-in-place

Main spans1

Design loadHS 20

Structure length26 ft (7.9 m)

Longest span26 ft (7.9 m)

Deck width34 ft (10.4 m)

Roadway width30 ft (9.1 m)

Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,500 (2022)

Projected traffic3,500 by 2043

Trucks21%

Lanes on structure2

Traffic directionTwo-way traffic

CarriesHighway

CrossesWaterway

Detour if closed18 mi (29 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 Drainage Ditch built?

It was built in 1958, making it 67 years old in 2025.

What condition is US 18 over Drainage Ditch 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 Drainage Ditch carry?

About 3,500 vehicles per day (2022 count), of which roughly 21% are trucks.

How long is US 18 over Drainage Ditch?

The structure is 26 ft (7.9 m) long with a longest span of 26 ft (7.9 m) and a deck 34 ft wide.

Who owns US 18 over Drainage Ditch?

It is owned by the State Highway Agency.