US Bridges

I-75 NB over Trowbridge RD

Fair

Cheboygan County, Michigan · 2.5 MI N of Otsego Col · Structure no. 000000000001524

Built
1962
63 years old, rebuilt 2024
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
252 ft
4 main spans
Daily traffic
7,875
2024 count
Owner
State
State Highway Agency

About this bridge

I-75 NB over Trowbridge RD is a steel stringer/multi-beam or girder carrying I-75 NB over Trowbridge RD in Cheboygan County, Michigan. It was built in 1962 and reconstructed in 2024, so it is 63 years old, older than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 7,875 vehicles a day, roughly 8% of them trucks, projected to reach 8,700 by 2044. The structure is 252 ft (76.7 m) long and 36 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-75 NB
CrossesTrowbridge RD
Location2.5 MI N of Otsego Col
RouteInterstate 75
CountyCheboygan County
StateMichigan
Coordinates45.22936, -84.58749
Functional classRural Principal Arterial - Interstate

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2024
Inspection intervalevery 17 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.4 US tons
Inventory rating54.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length252 ft (76.7 m)
Longest span67 ft (20.4 m)
Deck width36 ft (11.1 m)
Roadway width33 ft (10.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,875 (2024)
Projected traffic8,700 by 2044
Trucks8%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-75 NB over Trowbridge RD built?

It was built in 1962, making it 63 years old in 2025. It was reconstructed in 2024.

What condition is I-75 NB over Trowbridge RD in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in November 2024.

How much traffic does I-75 NB over Trowbridge RD carry?

About 7,875 vehicles per day (2024 count), of which roughly 8% are trucks.

How long is I-75 NB over Trowbridge RD?

The structure is 252 ft (76.7 m) long with a longest span of 67 ft (20.4 m) and a deck 36 ft wide.

Who owns I-75 NB over Trowbridge RD?

It is owned by the State Highway Agency.