Structure 9640 · Sanilac County, MI
Carries Wood Road over Duff Drain, Sec 22-23 Marlette Twp.
A culvert 23 ft across with 2 openings. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights, so those are drawn as typical for a culvert.
| State | Michigan |
| County | Sanilac |
| Location | Sec 22-23 Marlette Twp |
| Carries | Wood Road |
| Crosses | Duff Drain |
| Coordinates | 43.35910, -83.02543 |
| Material | Aluminum/Wrought Iron/Cast Iron |
| Design | Culvert |
| Total Length | 22.6 ft (6.9 m) |
| Max Span | 22.6 ft (6.9 m) |
| Deck Area | 54.5 sq m |
| Main Spans | 2 |
| Year Built | 2001 |
| Avg Daily Traffic | 130 (2016) |
| Truck Traffic | 10% |
| Lanes On Bridge | 2 |
| Last Inspection | April 2024 |
| Inspection Frequency | Every 24 months |
| Owner | County Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | 000000000009640 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.