Sidney Rd (CR 510) over Flat River
Montcalm County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Sidney Rd (CR 510) over Flat River in Montcalm County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1931, making it 94 years old at the 2025 inventory.
- It carries about 4,593 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 69 of the 121 inventoried bridges in Montcalm County rated fair (57.0%); 7 (5.8%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2023, on a 24-month routine inspection cycle.
- 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 → (43.25004, -85.29803)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 60 ft |
| Location | 0.25 Mi. E. of Johnson Rd |
| NBI structure number | 000000000007456 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2023 |
| Inspection interval (item 91) | 24 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 Montcalm County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US-131SB & M-46sb over Tamarack Creek | 1972 | 26,700 | Fair |
| US-131NB & M-46nb over Tamarack Creek | 1972 | 26,700 | Fair |
| US-131 & M-46 SB over Kendaville Rd | 1971 | 26,700 | Fair |
| US-131 & M-46 NB over Kendaville Rd | 1971 | 26,700 | Fair |
| M-57 over Flat River | 1948 | 11,727 | Good |
| M-91 over Flat River | 1994 | 11,433 | Fair |
All bridges nearby: Montcalm County, MI bridge conditions · every bridge in Montcalm County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.