M-138 over Allen Drain
Tuscola County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- M-138 over Allen Drain in Tuscola 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 1968, making it 57 years old at the 2025 inventory.
- It carries about 1,678 vehicles a day (traffic count year 2007).
- Its listed owner is the state highway agency.
- It is one of 149 of the 241 inventoried bridges in Tuscola County rated fair (61.8%); 10 (4.1%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: deck 6 to 5.
- Its most recent inspection on record is dated August 2024, 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 → (43.56626, -83.52331)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 5 | Fair condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 40 ft |
| Location | W Lts of Akron |
| NBI structure number | 000000000010400 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | August 2024 |
| 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 Tuscola County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-15 over Cass River | 2015 | 14,550 | Good |
| M-46 over Cheboygan & Branches Drn | 1939 | 6,701 | Poor |
| M-81 over Marsh Drain | 2007 | 6,273 | Good |
| M-25 over Quanicassee River | 2013 | 5,571 | Good |
| M-25 over (no Name) Drain | 1932 | 5,571 | Fair |
| M-25 over Wisner Drain | 1985 | 5,571 | Fair |
All bridges nearby: Tuscola County, MI bridge conditions · every bridge in Tuscola County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.