US 31 SB over S Branch Pentwater River
Oceana County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 31 SB over S Branch Pentwater River in Oceana County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1977 and reconstructed in 1987, making it 48 years old at the 2025 inventory.
- It carries about 4,171 vehicles a day (traffic count year 2007).
- Its listed owner is the state highway agency.
- It is one of 64 of the 101 inventoried bridges in Oceana County rated fair (63.4%); 5 (5.0%) 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 November 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 → (43.74154, -86.38989)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 211 ft |
| Location | 3 Mi NW of Hart |
| NBI structure number | 000000000008334 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | November 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Oceana County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US-31 SB over Grant Road | 1975 | 10,300 | Fair |
| US-31 NB over Grant Road | 1975 | 10,300 | Fair |
| US-31BR over Russell Creek | 2020 | 8,800 | Good |
| US-31 SB over Log Rd & CSX RR (abn) | 1975 | 8,500 | Fair |
| US-31 NB over Log Rd & CSX RR (abn) | 1975 | 8,500 | Fair |
| US-31 SB over Buchanan Road | 1975 | 8,500 | Fair |
All bridges nearby: Oceana County, MI bridge conditions · every bridge in Oceana County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.