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I-75 over Straits of Mackinac

Emmet County, Michigan · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

I-75 over Straits of Mackinac in Emmet County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
It was built in 1957, making it 68 years old at the 2025 inventory.
It carries about 11,926 vehicles a day (traffic count year 2021).
It is one of 16 of the 38 inventoried bridges in Emmet County rated fair (42.1%); 1 (2.6%) are rated poor.
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.

Component ratings

Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.

Bridge	Built	Vehicles/day	Condition
US-31\|W Mitchellst over Bear River	1930	28,667	Fair
I-75 S Appr over Huron Ave	1957	11,076	Fair
I-75 N Appr over Straits of Mackinac	1942	11,076	Fair
I-75 NB over D&m RR (abn)	1957	10,100	Fair
I-75 NB over Central St	1957	10,100	Fair
M-68 over Crooked River	1937	8,053	Fair