US 78 over Polk Swamp
FairDorchester County, South Carolina · 4 MI NW of ST George · Structure no. 000000000001621
- Built
- 1949
- 76 years old
- Condition
- Fair
- inspected April 2024
- Type
- Slab
- Concrete
- Length
- 112 ft
- 4 main spans
- Daily traffic
- 4,700
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 78 over Polk Swamp is a concrete slab carrying US 78 over Polk Swamp in Dorchester County, South Carolina. It was built in 1949, so it is 76 years old, older than the South Carolina average of 48 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 4,700 vehicles a day, roughly 10% of them trucks, projected to reach 8,178 by 2043. The structure is 112 ft (34.1 m) long and 29 ft wide. If it were closed, the detour would be 1.9 mi (3 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| 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 US 78 over Polk Swamp built?
It was built in 1949, making it 76 years old in 2025.
What condition is US 78 over Polk Swamp 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 April 2024.
How much traffic does US 78 over Polk Swamp carry?
About 4,700 vehicles per day (2023 count), of which roughly 10% are trucks.
How long is US 78 over Polk Swamp?
The structure is 112 ft (34.1 m) long with a longest span of 28 ft (8.5 m) and a deck 29 ft wide.
Who owns US 78 over Polk Swamp?
It is owned by the State Highway Agency.