478th Ave HWY 121 over Slip-Up Creek
FairMinnehaha County, South Dakota · 3.5E & 2.7N Renner · Structure no. 000000050240113
- Built
- 1970
- 55 years old
- Condition
- Fair
- inspected June 2024
- Type
- Slab
- Concrete Continuous
- Length
- 73 ft
- 3 main spans
- Daily traffic
- 1,381
- 2023 count
- Owner
- County
- County Highway Agency
About this bridge
478th Ave HWY 121 over Slip-Up Creek is a concrete continuous slab carrying 478th Ave HWY 121 over Slip-Up Creek in Minnehaha County, South Dakota. It was built in 1970, so it is 55 years old, older 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 1,381 vehicles a day, roughly 12% of them trucks, projected to reach 1,603 by 2038. The structure is 73 ft (22.4 m) long and 35 ft wide. If it were closed, the detour would be 6.2 mi (10 km).
Location
Open in Google MapsCondition and inspection
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. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was 478th Ave HWY 121 over Slip-Up Creek built?
It was built in 1970, making it 55 years old in 2025.
What condition is 478th Ave HWY 121 over Slip-Up 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 June 2024.
How much traffic does 478th Ave HWY 121 over Slip-Up Creek carry?
About 1,381 vehicles per day (2023 count), of which roughly 12% are trucks.
How long is 478th Ave HWY 121 over Slip-Up Creek?
The structure is 73 ft (22.4 m) long with a longest span of 28 ft (8.4 m) and a deck 35 ft wide.
Who owns 478th Ave HWY 121 over Slip-Up Creek?
It is owned by the County Highway Agency.