M-66 NB over I-96
Ionia County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- M-66 NB over I-96 in Ionia County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1959, making it 66 years old at the 2025 inventory.
- It carries about 10,500 vehicles a day (traffic count year 2016).
- Its listed owner is the state highway agency.
- It is one of 69 of the 118 inventoried bridges in Ionia County rated fair (58.5%); 12 (10.2%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- It was rated good in the 2024 inventory and is now fair (deck 7 to 6, superstructure 7 to 5, substructure 7 to 5).
- Its most recent inspection on record is dated October 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 → (42.87936, -85.07481)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 6 | Satisfactory condition |
| Superstructure | 7 | 5 | Fair condition |
| Substructure | 7 | 5 | Fair condition |
Bridge details
| Structure | Continuous concrete tee beam |
| Length | about 268 ft |
| Location | @ M-66 |
| NBI structure number | 000000000003985 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Ionia County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-96 over Portland Trail | 2013 | 35,000 | Good |
| I-96 over Libhart Creek | 1958 | 33,978 | Fair |
| I-96 EB over Kent Rd | 1959 | 20,074 | Fair |
| I-96 WB over Kent Rd | 1959 | 20,074 | Fair |
| I-96 EB over Okemos Rd | 1959 | 20,074 | Fair |
| I-96 WB over Okemos Rd | 1959 | 20,074 | Fair |
All bridges nearby: Ionia County, MI bridge conditions · every bridge in Ionia County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.