US Bridges

IRR US018 over White Horse Ck

Fair

Todd County, South Dakota · 3.8 W Tripp CO Line · Structure no. 000000061485010

Built
2016
9 years old
Condition
Fair
inspected August 2024
Type
Culvert
Concrete Continuous
Length
68 ft
5 main spans
Daily traffic
1,303
2024 count
Owner
State
State Highway Agency

About this bridge

IRR US018 over White Horse Ck is a concrete continuous culvert carrying IRR US018 over White Horse Ck in Todd County, South Dakota. It was built in 2016, so it is 9 years old, younger than the South Dakota average of 48.9 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 1,303 vehicles a day, roughly 17% of them trucks, projected to reach 1,902 by 2044. The structure is 68 ft (20.7 m) long. If it were closed, the detour would be 29.8 mi (48 km).

CarriesIRR US018
CrossesWhite Horse Ck
Location3.8 W Tripp CO Line
RouteU.S. Route 18
Coordinates43.37543, -100.28361
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
Channel and channel protection8 Very GoodNo problems noted.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment9: Superior to present desirable criteria
Operating rating38 US tons
Inventory rating29.3 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans5
Design loadHL 93
Structure length68 ft (20.7 m)
Longest span13 ft (4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,303 (2024)
Projected traffic1,902 by 2044
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 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 IRR US018 over White Horse Ck built?

It was built in 2016, making it 9 years old in 2025.

What condition is IRR US018 over White Horse Ck 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 2024.

How much traffic does IRR US018 over White Horse Ck carry?

About 1,303 vehicles per day (2024 count), of which roughly 17% are trucks.

How long is IRR US018 over White Horse Ck?

The structure is 68 ft (20.7 m) long with a longest span of 13 ft (4 m).

Who owns IRR US018 over White Horse Ck?

It is owned by the State Highway Agency.