Structure 8004 · Oakland County, MI

I-75 NB over Pontiac RD

Carries I-75 NB over Pontiac RD, 2.0 Mi N Of M-59.

Overall conditionFair

Set by its lowest-rated component: Superstructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT130 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

130 ft end to end, longest span 63 ft. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built196363 years old
Length129.9 ft39.6 m
Daily traffic71,900counted 2009
Last inspectedSeptember 2024every 24 months

Location

StateMichigan
CountyOakland
Location2.0 Mi N Of M-59
CarriesI-75 NB
CrossesPontiac RD
Coordinates42.67094, -83.24102

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length129.9 ft (39.6 m)
Max Span62.7 ft (19.1 m)
Deck Width72.8 ft (22.2 m)
Deck Area879.1 sq m
Main Spans3
Year Built1963

Traffic

Avg Daily Traffic71,900 (2009)
Truck Traffic4%
Lanes On Bridge5
Lanes Under Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number000000000008004

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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