US Bridges

US 20 over Drainage Ditch #4

Good

Hamilton County, Iowa · 1.8 Miles East of US 69 · Structure no. 000000000026610

Built
1968
57 years old
Condition
Good
inspected June 2023
Type
Culvert
Concrete Continuous
Length
28 ft
2 main spans
Daily traffic
9,600
2022 count
Owner
State
State Highway Agency

About this bridge

US 20 over Drainage Ditch #4 is a concrete continuous culvert carrying US 20 over Drainage Ditch #4 in Hamilton County, Iowa. It was built in 1968, so it is 57 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 9,600 vehicles a day, roughly 27% of them trucks, projected to reach 9,600 by 2042. The structure is 28 ft (8.5 m) long. If it were closed, the detour would be 3.7 mi (6 km).

CarriesUS 20
CrossesDrainage Ditch #4
Location1.8 Miles East of US 69
RouteU.S. Route 20
StateIowa
Coordinates42.44887, -93.60477
Functional classRural Principal Arterial - Other

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54.2 US tons
Inventory rating32.5 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20
Structure length28 ft (8.5 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,600 (2022)
Projected traffic9,600 by 2042
Trucks27%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 20 over Drainage Ditch #4 built?

It was built in 1968, making it 57 years old in 2025.

What condition is US 20 over Drainage Ditch #4 in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2023.

How much traffic does US 20 over Drainage Ditch #4 carry?

About 9,600 vehicles per day (2022 count), of which roughly 27% are trucks.

How long is US 20 over Drainage Ditch #4?

The structure is 28 ft (8.5 m) long with a longest span of 12 ft (3.7 m).

Who owns US 20 over Drainage Ditch #4?

It is owned by the State Highway Agency.