US Bridges

I-75 Bl NB over Gtw RR

Fair

Oakland County, Michigan · S Lts of Pontiac · Structure no. 000000000007982

Built
1966
59 years old, rebuilt 2004
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
236 ft
4 main spans
Daily traffic
37,709
2007 count
Owner
State
State Highway Agency

About this bridge

I-75 Bl NB over Gtw RR is a steel stringer/multi-beam or girder carrying I-75 Bl NB over Gtw RR in Oakland County, Michigan. It was built in 1966 and reconstructed in 2004, so it is 59 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 37,709 vehicles a day, roughly 1% of them trucks, projected to reach 37,414 by 2018. The structure is 236 ft (71.8 m) long and 49 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesI-75 Bl NB
CrossesGtw RR
LocationS Lts of Pontiac
RouteInterstate 75
CountyOakland County
StateMichigan
Coordinates42.60383, -83.25246
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating63.9 US tons
Inventory rating38.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 25 or greater
Structure length236 ft (71.8 m)
Longest span78 ft (23.8 m)
Deck width49 ft (14.8 m)
Roadway width45 ft (13.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic37,709 (2007)
Projected traffic37,414 by 2018
Trucks1%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

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 Bl NB over Gtw RR built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 2004.

What condition is I-75 Bl NB over Gtw RR 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 July 2023.

How much traffic does I-75 Bl NB over Gtw RR carry?

About 37,709 vehicles per day (2007 count), of which roughly 1% are trucks.

How long is I-75 Bl NB over Gtw RR?

The structure is 236 ft (71.8 m) long with a longest span of 78 ft (23.8 m) and a deck 49 ft wide.

Who owns I-75 Bl NB over Gtw RR?

It is owned by the State Highway Agency.