County profile · official public datasets

Lapeer County, MI

163 public highway bridges tracked in the FHWA National Bridge Inventory: 36.2% rated Good, 54.6% Fair, 9.2% Poor.

163
Public bridges: 36.2%
Good condition: 9.2%
Poor condition

The verdict

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

Lapeer 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 43%
lowest Poor share in state: 9.2%
Poor-condition share: 163
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.

Lapeer County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Lapeer County ranks #36 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.2%). Lapeer County, Michigan contains 163 public highway bridges. Roughly 36.2% are rated “Good,” 54.6% “Fair,” and 9.2% “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

163

Public highway bridges in Lapeer County

Good condition

36.2%

59 of 163 rated 7-9

Fair condition

54.6%

89 of 163 rated 5-6

Poor condition

9.2%

15 of 163 rated 4 or below

In-state Poor-share rank

#36 of 83

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

Condition distribution

Share of 163 NBI-tracked bridges by lowest applicable component rating.

Good

36.2% (59)

Fair

54.6% (89)

Poor

9.2% (15)

Lapeer County's Poor-condition bridges carry 49,222 vehicle crossings a day

That is 7.2% of the county's reported daily bridge traffic on 9.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,281 crossings a day against 3,549 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 163 of 163 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

27% of Lapeer County's bridges have passed the 50-year mark

44 of the 163 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 36.2% 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 37.5% of the county's Poor-condition bridge traffic

M-24 over S BR FLINT RIVER, built 1948, carries 18,440 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 15-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 49,222 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

1
1930s

4
1940s

5
1950s

2
1960s

17
1970s

39
1980s

49
1990s

23
2000s

8
2010s

12
2020s

3

What this shows Construction peaked in the 1980s, when 49 of the county's bridges still in the inventory were built, which is 30.1% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1982, 6 years newer than the Michigan average of 1976.

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

The 5 Michigan counties nearest Lapeer County in number of bridges, with their condition splits. Its 9.2% Poor share is the 2nd-lowest of these 6. Its average build year of 1982 against a peer-group mean of 1976 is 6 years newer.

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

Bridge inventory size and condition shares for Lapeer County and the 5 Michigan counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Gratiot County	167	40.7%	47.3%	12%	1975
Bay County	166	30.1%	53%	16.9%	1974
Livingston County	165	26.7%	58.8%	14.5%	1974
Shiawassee County	163	45.4%	45.4%	9.2%	1981
Lapeer County (this page)	163	36.2%	54.6%	9.2%	1982
Jackson County	158	34.2%	55.7%	10.1%	1978

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 Lapeer 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 Lapeer County, both outside Michigan so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside MI (163 bridges here).

Mercer County, IL · 163 bridges
Jennings County, IN · 163 bridges
Wayne County, IA · 163 bridges
Jackson County, LA · 163 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 163 Good 59 Fair 89 Poor 15

Good-condition bridges (59)

Sort:

Lapeer County Bridge Snapshot

Condition distribution

Lapeer County's Poor-condition bridges carry 49,222 vehicle crossings a day

27% of Lapeer County's bridges have passed the 50-year mark

One structure carries 37.5% of the county's Poor-condition bridge traffic

How Lapeer 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

Good-condition bridges (59)

MAYFIELD ROAD

BARNES LAKE ROAD

GENESEE ROAD

NORWAY LAKE ROAD

BROWN CITY ROAD

MUIR ROAD

THORNVILLE ROAD

DEMILLE ROAD

COLUMBIAVILLE ROAD

NEWARK ROAD

MAPLE GROVE ROAD

MCTAGGART ROAD

CADE ROAD

GREENWOOD ROAD

M-24

MERRILL ROAD

MONROE STREET

WILDER ROAD

EB I-69

M-53

I-69 WB RAMP

FARNSWORTH ROAD

FLINT RIVER ROAD

STANLEY ROAD

GRAVES ROAD

ALMONT ROAD

CHERRY STREET

LAKE NEPESSING RD

I-69 WB

COURT STREET

SAGINAW ROAD

THORNVILLE ROAD

MARTUS ROAD

NEPESSING STREET

E IMLAY CITY RD

WHEELING ROAD

BARNES ROAD

ARMSTRONG ROAD

MASON STREET

MILLINGTON ROAD

I-69 EB RAMP

SECOND STREET

IMLAY CITY ROAD

CASTLE ROAD

NEWARK ROAD

GARDNER RD

I-69 WB

HATHAWAY ROAD

MARATHON ROAD

BENTLEY STREET

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