S Harper Drive over Little Manistee River
Lake County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S Harper Drive over Little Manistee River in Lake County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1979, making it 46 years old at the 2025 inventory.
- It carries about 115 vehicles a day (traffic count year 2007).
- Its listed owner is the county highway agency.
- It is one of 13 of the 31 inventoried bridges in Lake County rated fair (41.9%); 5 (16.1%) 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 May 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 → (44.11551, -85.97305)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete multiple box beam |
| Length | about 51 ft |
| Location | 3 Miles SW of Irons |
| NBI structure number | 000000000005292 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Lake County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-37 over Pere Marquette River | 1922 | 4,771 | Fair |
| M-37 over Baldwin Creek | 1929 | 4,771 | Fair |
| US-10 over Baldwin Creek | 1931 | 3,813 | Fair |
| US-10 over Sanborn Creek | 1934 | 3,813 | Fair |
| M-37 over Little Manistee River | 1939 | 2,500 | Good |
| 56 Th Street FH32 over Pere Marquette River | 1997 | 1,400 | Good |
All bridges nearby: Lake County, MI bridge conditions · every bridge in Lake County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.