M-21 over Flat River
Good Condition86 years old18,836 vehicles/day
Location
| State | Michigan |
| County | Kent |
| Location | In Lowell (107 E Main St) |
| Carries | M-21 |
| Crosses | Flat River |
| Coordinates | 42.93441, -85.33805 |
Condition Ratings
| Overall Condition | Good |
| Deck | 7 (Good) |
| Superstructure | 8 (Very Good) |
| Substructure | 7 (Good) |
| Channel/Waterway | 8 (Very Good) |
| Scour Critical | 7 — Countermeasures installed |
Physical Characteristics
| Material | Prestressed Concrete |
| Design | Box Beam - Single/Spread |
| Total Length | 48.9 ft (14.9 m) |
| Max Span | 46.3 ft (14.1 m) |
| Deck Width | 74.1 ft (22.6 m) |
| Deck Area | 336.7 sq m |
| Main Spans | 1 |
| Year Built | 1940 (reconstructed 2010) |
Traffic
| Avg Daily Traffic | 18,836 (2007) |
| Truck Traffic | 4% |
| Lanes On Bridge | 4 |
Inspection & Ownership
| Last Inspection | October 2024 |
| Inspection Frequency | Every 24 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Structure Number | 000000000004856 |