US Bridges

I-75 SB over Coolidge RD

Good

Oakland County, Michigan · In Troy · Structure no. 000000000008078

Built
2020
5 years old
Condition
Good
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
114 ft
1 main span
Daily traffic
79,250
2016 count
Owner
State
State Highway Agency

About this bridge

I-75 SB over Coolidge RD is a prestressed concrete stringer/multi-beam or girder carrying I-75 SB over Coolidge RD in Oakland County, Michigan. It was built in 2020, so it is 5 years old, younger than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 79,250 vehicles a day, roughly 8% of them trucks, projected to reach 96,100 by 2038. The structure is 114 ft (34.6 m) long and 74 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-75 SB
CrossesCoolidge RD
LocationIn Troy
RouteInterstate 75
CountyOakland County
StateMichigan
Coordinates42.60473, -83.18883
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69.7 US tons
Inventory rating39.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadGreater than HL 93
Structure length114 ft (34.6 m)
Longest span114 ft (34.6 m)
Deck width74 ft (22.5 m)
Roadway width71 ft (21.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic79,250 (2016)
Projected traffic96,100 by 2038
Trucks8%
Lanes on structure4
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 SB over Coolidge RD built?

It was built in 2020, making it 5 years old in 2025.

What condition is I-75 SB over Coolidge RD in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2023.

How much traffic does I-75 SB over Coolidge RD carry?

About 79,250 vehicles per day (2016 count), of which roughly 8% are trucks.

How long is I-75 SB over Coolidge RD?

The structure is 114 ft (34.6 m) long with a longest span of 114 ft (34.6 m) and a deck 74 ft wide.

Who owns I-75 SB over Coolidge RD?

It is owned by the State Highway Agency.