Grassmere Road over Pinnebog River
Huron County, Michigan · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Grassmere Road over Pinnebog River in Huron County, Michigan, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1929, making it 96 years old at the 2025 inventory.
- It carries about 150 vehicles a day (traffic count year 2009).
- Its listed owner is the county highway agency.
- It is one of 14 of the 192 inventoried bridges in Huron County rated poor (7.3%); 14 (7.3%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- It was rated fair in the 2024 inventory and is now poor (deck 5 to 4, superstructure 5 to 4).
- Its most recent inspection on record is dated September 2024, on a 12-month routine inspection cycle.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (43.78612, -83.12054)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 4 | Poor condition |
| Superstructure | 5 | 4 | Poor condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 41 ft |
| Location | Sec. 30 Colfax Twp |
| NBI structure number | 000000000003586 |
| Condition class | Poor |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 12 months |
| Scour (item 113) | U: unknown foundation, not evaluated for scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Huron County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Anton Street over Sebewaing River | 2013 | 5,590 | Good |
| M-142 over Pinnebog River | 1946 | 5,274 | Good |
| M-142|pigeon Rd over Nettle Run | 2012 | 5,200 | Good |
| M-25 over Sebewaing River | 1949 | 5,123 | Fair |
| Center Street over Sebewaing River | 2003 | 4,900 | Fair |
| M-25 over Pigeon River | 1929 | 4,865 | Good |
All bridges nearby: Huron County, MI bridge conditions · every bridge in Huron County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.