M-21 over Rush Creek
Shiawassee County, Michigan · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- M-21 over Rush Creek in Shiawassee County, Michigan, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 8 (very good condition) on the 0-9 scale.
- It was built in 2022, making it 3 years old at the 2025 inventory.
- It carries about 9,700 vehicles a day (traffic count year 2018).
- Its listed owner is the state highway agency.
- It is one of 72 of the 163 inventoried bridges in Shiawassee County rated good (44.2%); 15 (9.2%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (42.99954, -83.98659)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 8 | Very good condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 33 ft |
| Location | 2.8 Mi W of Genesee Col |
| NBI structure number | 000000000009777 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Shiawassee County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-69 EB over Looking Glass River | 1961 | 192,000 | Fair |
| I-69 WB over Looking Glass River | 1961 | 192,000 | Fair |
| I-69 EB over Holly Drain | 1961 | 192,000 | Fair |
| I-69 WB over Holly Drain | 1961 | 192,000 | Fair |
| Britton Rd over I-69 | 1989 | 25,000 | Fair |
| M-21 over Shiawassee River | 1970 | 22,689 | Fair |
All bridges nearby: Shiawassee County, MI bridge conditions · every bridge in Shiawassee County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.