Ky-18 over Allen Fork
Boone County, Kentucky · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Ky-18 over Allen Fork in Boone County, Kentucky, 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 1958, making it 67 years old at the 2025 inventory.
- It carries about 6,768 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 74 of the 139 inventoried bridges in Boone County rated fair (53.2%); 8 (5.8%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated June 2023, on a 48-month routine inspection cycle.
- 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 → (39.02833, -84.74694)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 42 ft |
| Location | 1.2 Mi West of Jct Ky 338 |
| NBI structure number | 008B00012N |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | June 2023 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Kentucky department of transportation.
Busiest bridges in Boone County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-75 over Ky 18 Ramp | 1990 | 140,378 | Fair |
| I-75 Ramp over West Rmp KY18 to I75SB | 1990 | 140,378 | Fair |
| I-75 over Chambers Lane | 1960 | 112,428 | Fair |
| I-75 Nc over Turfway Road (ky 1017) | 1960 | 90,720 | Fair |
| I-75 over Turfway Road (ky 1017) | 1960 | 90,720 | Fair |
| I-75 Nc over Ky 536 (mt Zion Rd) | 1992 | 70,784 | Fair |
All bridges nearby: Boone County, KY bridge conditions · every bridge in Boone County · Kentucky bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.