US Bridges

US 20 over Unnamed Stream

Good

Sac County, Iowa · 3.7 Mi. W of Jct. US 71 · Structure no. 000000000046541

Built
2017
8 years old
Condition
Good
inspected December 2023
Type
Culvert
Concrete
Length
25 ft
2 main spans
Daily traffic
4,850
2022 count
Owner
State
State Highway Agency

About this bridge

US 20 over Unnamed Stream is a concrete culvert carrying US 20 over Unnamed Stream in Sac County, Iowa. It was built in 2017, so it is 8 years old, younger 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 4,850 vehicles a day, roughly 37% of them trucks, projected to reach 4,850 by 2043. The structure is 25 ft (7.6 m) long. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesUS 20
CrossesUnnamed Stream
Location3.7 Mi. W of Jct. US 71
RouteU.S. Route 20
CountySac County
StateIowa
Coordinates42.47491, -95.22061
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 protection8 Very GoodNo problems noted.
Culvert8 Very GoodNo problems noted.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHL 93
Structure length25 ft (7.6 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 traffic4,850 (2022)
Projected traffic4,850 by 2043
Trucks37%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 Unnamed Stream built?

It was built in 2017, making it 8 years old in 2025.

What condition is US 20 over Unnamed Stream 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 December 2023.

How much traffic does US 20 over Unnamed Stream carry?

About 4,850 vehicles per day (2022 count), of which roughly 37% are trucks.

How long is US 20 over Unnamed Stream?

The structure is 25 ft (7.6 m) long with a longest span of 12 ft (3.7 m).

Who owns US 20 over Unnamed Stream?

It is owned by the State Highway Agency.