Harmon Lake Road over S. O. Drain
Tuscola County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Harmon Lake Road over S. O. Drain in Tuscola County, Michigan, 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 1997, making it 28 years old at the 2025 inventory.
- It carries about 85 vehicles a day (traffic count year 2009).
- Its listed owner is the county highway agency.
- It is one of 149 of the 241 inventoried bridges in Tuscola County rated fair (61.8%); 10 (4.1%) 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 → (43.39504, -83.33662)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 21 ft |
| Location | Sec 6-7 Dayton Twp |
| NBI structure number | 000000000010566 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Tuscola County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-15 over Cass River | 2015 | 14,550 | Good |
| M-46 over Cheboygan & Branches Drn | 1939 | 6,701 | Poor |
| M-81 over Marsh Drain | 2007 | 6,273 | Good |
| M-25 over Quanicassee River | 2013 | 5,571 | Good |
| M-25 over (no Name) Drain | 1932 | 5,571 | Fair |
| M-25 over Wisner Drain | 1985 | 5,571 | Fair |
All bridges nearby: Tuscola County, MI bridge conditions · every bridge in Tuscola County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.