County profile · official public datasets

Oakland County, MI

508 public highway bridges tracked in the FHWA National Bridge Inventory: 41.5% rated Good, 51% Fair, 7.5% Poor.

508
Public bridges: 41.5%
Good condition: 7.5%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Oakland County pairs a better-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

Top 34%
lowest Poor share in state: 7.5%
Poor-condition share: 508
public highway bridges: 1982
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Oakland County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Oakland County ranks #28 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.5%). Oakland County, Michigan contains 508 public highway bridges. Roughly 41.5% are rated “Good,” 51% “Fair,” and 7.5% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

Total bridges

508

Public highway bridges in Oakland County

Good condition

41.5%

211 of 508 rated 7-9

Fair condition

51%

259 of 508 rated 5-6

Poor condition

7.5%

38 of 508 rated 4 or below

In-state Poor-share rank

#28 of 83

Among Michigan counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 508 NBI-tracked bridges by lowest applicable component rating.

Good

41.5% (211)

Fair

51% (259)

Poor

7.5% (38)

Oakland County's Poor-condition bridges carry 449,398 vehicle crossings a day

That is 3.6% of the county's reported daily bridge traffic on 7.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 11,826 crossings a day against 25,061 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 507 of 508 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

45.5% of Oakland County's bridges have passed the 50-year mark

231 of the 508 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 41.5% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 46.6% of the county's Poor-condition bridge traffic

I-696 over I-75 & 4 RAMPS, built 1971, carries 209,200 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 38-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 449,398 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

1
1920s

6
1930s

9
1940s

5
1950s

30
1960s

125
1970s

70
1980s

84
1990s

54
2000s

49
2010s

40
2020s

35

What this shows Construction peaked in the 1960s, when 125 of the county's bridges still in the inventory were built, which is 24.6% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1982, 6 years newer than the Michigan average of 1976.

How Oakland County compares with Michigan's closest counties by inventory size

The 5 Michigan counties nearest Oakland County in number of bridges, with their condition splits. Its 7.5% Poor share is the 2nd-lowest of these 6. Its average build year of 1982 against a peer-group mean of 1977 is 5 years newer.

Showing the 5 closest of 82 Michigan counties eligible for comparison.

Bridge inventory size and condition shares for Oakland County and the 5 Michigan counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Kent County	523	36.9%	57.7%	5.4%	1975
Oakland County (this page)	508	41.5%	51%	7.5%	1982
Macomb County	417	42.7%	49.6%	7.7%	1980
Genesee County	371	22.9%	61.7%	15.4%	1968
St. Clair County	327	41.3%	50.5%	8.3%	1985
Saginaw County	315	28.9%	52.7%	18.4%	1979

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Oakland County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Oakland County, both outside Michigan so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside MI (508 bridges here).

Morris County, NJ · 508 bridges
Wood County, OH · 508 bridges
Douglas County, NE · 509 bridges
Linn County, IA · 506 bridges

Similar average build year

Nearest mean year-built outside MI (1982 here).

Oklahoma County, OK · avg 1982 · 1,216 bridges
Jackson County, MO · avg 1982 · 930 bridges
Milwaukee County, WI · avg 1982 · 893 bridges
Champaign County, IL · avg 1982 · 727 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 508 Good 211 Fair 259 Poor 38

All bridges (508)

Sort:

Oakland County Bridge Snapshot

Condition distribution

Oakland County's Poor-condition bridges carry 449,398 vehicle crossings a day

45.5% of Oakland County's bridges have passed the 50-year mark

One structure carries 46.6% of the county's Poor-condition bridge traffic

How Oakland County compares with Michigan's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (508)

M-150

ORCHARD LAKE ROAD

PONTIAC RD

PLAZA & CHURCH ST

BUNO ROAD

SQUIRREL RD NB

SQUIRREL RD SB

CHICAGO ROAD

STEPHENSON HWY

WOODWARD U TURN W

RIVERVIEW DR

NOVI RD

US-24 & US-10

LAHSER ROAD

COOLIDGE ROAD U TU

GILLESPIE AVE

EVERGREEN ROAD

CAMPBELL AVE

SOUTHFIELD U TURN

INDIAN VIEW DRIVE

I-96

SCOTIA ROAD

LANSDOWNE RD

MILL

WARNER STREET

ADAMS ROAD

M-39 NB

GREENFIELD ROAD

HARVARD

BELFORD RD

U-TURN W.OF GRNFLD

MOHAWK AVENUE

CORPORATE DR

WASHINGTON

M-5 SB MAINLINE

M-59 (E HURON ST)

I-96 BL (GRAND RV)

I-75 BR

CROOKS ROAD

NINE MILE ROAD

SOUTHFIELD RD

MAIN STREET

ROANOKE U-TURN

ROCHESTER RD

ROCHESTER RD

WALDON RD

WILLOWBROOK ST

CRANBROOKE DRIVE

CIVIC CENTER DRIVE

NORTHFIELD PARKWAY

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