478th Ave HWY 121 over Slip-Up Ck
GoodMinnehaha County, South Dakota · 4E & 3.5S Baltic · Structure no. 000000050240095
- Built
- 2014
- 11 years old
- Condition
- Good
- inspected June 2023
- Type
- Slab
- Concrete Continuous
- Length
- 77 ft
- 3 main spans
- Daily traffic
- 1,340
- 2023 count
- Owner
- County
- County Highway Agency
About this bridge
478th Ave HWY 121 over Slip-Up Ck is a concrete continuous slab carrying 478th Ave HWY 121 over Slip-Up Ck in Minnehaha County, South Dakota. It was built in 2014, so it is 11 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 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 1,340 vehicles a day, roughly 12% of them trucks, projected to reach 1,555 by 2038. The structure is 77 ft (23.6 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
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| 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 Ck built?
It was built in 2014, making it 11 years old in 2025.
What condition is 478th Ave HWY 121 over Slip-Up Ck 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 478th Ave HWY 121 over Slip-Up Ck carry?
About 1,340 vehicles per day (2023 count), of which roughly 12% are trucks.
How long is 478th Ave HWY 121 over Slip-Up Ck?
The structure is 77 ft (23.6 m) long with a longest span of 29 ft (8.8 m) and a deck 35 ft wide.
Who owns 478th Ave HWY 121 over Slip-Up Ck?
It is owned by the County Highway Agency.