I-81 Nbl over Duncan Run
Frederick County, Virginia · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I-81 Nbl over Duncan Run in Frederick County, Virginia, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1965, making it 60 years old at the 2025 inventory.
- It carries about 26,774 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 105 of the 168 inventoried bridges in Frederick County rated fair (62.5%); 3 (1.8%) are rated poor.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (39.28669, -78.08648)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 38 ft |
| Location | 2.23 to 672 - 0.31 to 669 |
| NBI structure number | 000000000008143 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Virginia department of transportation.
Busiest bridges in Frederick County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-81 over Stephens Run | 1965 | 55,640 | Good |
| I-81 over Thomas Run | 1965 | 53,468 | Good |
| I-81 Nbl over Route 11 | 1964 | 35,288 | Fair |
| I-81 Nbl over Abrams Creek & Pvt Rd | 1964 | 35,134 | Fair |
| I-81 Sbl over Abrams Creek & Pvt Rd | 1964 | 34,099 | Fair |
| I-81 Nbl over CSX Transportation | 1964 | 33,000 | Fair |
All bridges nearby: Frederick County, VA bridge conditions · every bridge in Frederick County · Virginia bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.