County profile · official public datasets

Gratiot County, MI

167 public highway bridges tracked in the FHWA National Bridge Inventory: 40.7% rated Good, 47.3% Fair, 12% Poor.

167
Public bridges
40.7%
Good condition
12%
Poor condition

The verdict

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

Gratiot County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

45th
of 83 on Poor share
12%
Poor-condition share
167
public highway bridges
1975
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.

Gratiot County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Gratiot County ranks #45 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 12%). Gratiot County, Michigan contains 167 public highway bridges. Roughly 40.7% are rated “Good,” 47.3% “Fair,” and 12% “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

167

Public highway bridges in Gratiot County

Good condition

40.7%

68 of 167 rated 7-9

Fair condition

47.3%

79 of 167 rated 5-6

Poor condition

12%

20 of 167 rated 4 or below

In-state Poor-share rank

#45 of 83

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

Condition distribution

Share of 167 NBI-tracked bridges by lowest applicable component rating.

Good
40.7% (68)
Fair
47.3% (79)
Poor
12% (20)

Gratiot County's Poor-condition bridges carry 67,679 vehicle crossings a day

That is 18.1% of the county's reported daily bridge traffic on 12% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,384 crossings a day against 1,128 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 167 of 167 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

41.3% of Gratiot County's bridges have passed the 50-year mark

69 of the 167 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 40.7% 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 16.6% of the county's Poor-condition bridge traffic

M-46 & US-127BR over US-127, built 1961, carries 11,219 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 20-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 67,679 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Gratiot County's bridges were built

167 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 34 of the county's bridges still in the inventory were built, which is 20.4% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1975) matches the Michigan average (1976).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 Michigan counties nearest Gratiot County in number of bridges, with their condition splits. Its 12% Poor share is the 4th-lowest of these 6. Its average build year of 1975 against a peer-group mean of 1978 is in line with the group.

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

Bridge inventory size and condition shares for Gratiot County and the 5 Michigan counties closest to it in inventory size
County Bridges Poor
Sanilac County 171 9.9%
Gratiot County (this page) 167 12%
Bay County 166 16.9%
Livingston County 165 14.5%
Lapeer County 163 9.2%
Shiawassee County 163 9.2%

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

Similar inventory size

Nearest county inventories outside MI (167 bridges here).

Similar average build year

Nearest mean year-built outside MI (1975 here).

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

All 167 Good 68 Fair 79 Poor 20

Good-condition bridges (68)

MCCLELLAND ROAD

Good

Over: DRAIN # 142 OUTLET

SEC 19-20 ELBA TWP, Gratiot, MI

Built 1985 Load: 26.4 t ADT: 141

ALLEN ROAD

Good

Over: WOLF & BEAR CREEK DRAIN

SEC 12 WASHINGTON TWP, Gratiot, MI

Built 1986 Load: 27.4 t ADT: 71

TYLER ROAD

Good

Over: PINE RIVER

SEC 18-19 ARCADA TWP, Gratiot, MI

Built 1986 Load: 29.2 t ADT: 155

WEST CO LINE ROAD

Good

Over: NORTH BR PINE RIVER

SEC 07 SEVILLE TWP, Gratiot, MI

Built 1988 Load: 29.4 t ADT: 61

BALDWIN ROAD

Good

Over: DRAIN #115

SEC 3-4 NORTH STAR TWP, Gratiot, MI

Built 1988 Load: 30.8 t ADT: 610

WILSON ROAD

Good

Over: CORDRAY DRAIN

SEC. 25-36 WASHINGTON TWP, Gratiot, MI

Built 2011 Load: 32.4 t ADT: 333

GRANT ROAD

Good

Over: NORTH SHADE DRAIN

SEC 36 NEW HAVEN TWP, Gratiot, MI

Built 2004 Load: 32.7 t ADT: 615

GRANT ROAD

Good

Over: DRAIN #135

SEC 35 NEWARK TWP, Gratiot, MI

Built 2008 Load: 32.7 t ADT: 395

ST CHARLES ROAD

Good

Over: SHAD CREEK DRAIN

SEC 29-32 LAFAYETTE TWP, Gratiot, MI

Built 1980 Load: 32.7 t ADT: 164

MCCLELLAND ROAD

Good

Over: SHAD CREEK DRAIN

SEC 29-30 LAFAYETTE TWP, Gratiot, MI

Built 1981 Load: 32.7 t ADT: 132

RANSOM ROAD

Good

Over: SHAD CREEK DRAIN

SEC 32-33 LAFAYETTE TWP, Gratiot, MI

Built 1978 Load: 32.7 t ADT: 111

GRANT ROAD

Good

Over: BEAR CREEK DRAIN

SEC 32 NORTH STAR TWP, Gratiot, MI

Built 1979 Load: 32.7 t ADT: 99

GARFIELD ROAD

Good

Over: BEAR CREEK

SEC 1-12 WASHINGTON TWP, Gratiot, MI

Built 2003 Load: 32.7 t ADT: 219

BALDWIN ROAD

Good

Over: BEAR CREEK

WASHINGTON TWP SEC 3-4, Gratiot, MI

Built 2010 Load: 32.7 t ADT: 100

WISNER ROAD

Good

Over: BAD RIVER

SEC 18 HAMILTON TWP, Gratiot, MI

Built 1978 Load: 33.6 t ADT: 480

ENNIS ROAD

Good

Over: DRAIN #1

SEC 29 NEWARK TWP, Gratiot, MI

Built 1985 Load: 33.6 t ADT: 81

STATE ROAD

Good

Over: MAPLE RIVER

SEC 30 WASHINGTON TWP, Gratiot, MI

Built 1984 Load: 34.2 t ADT: 660

ALGER ROAD

Good

Over: DRAIN #1

SEC 15-16 NEWARK TWP, Gratiot, MI

Built 1986 Load: 34.3 t ADT: 1,145

MASON ROAD

Good

Over: BEAVER CREEK

SEC 35-36 WHEELER TWP, Gratiot, MI

Built 1983 Load: 34.5 t ADT: 95

CHEESMAN ROAD

Good

Over: PINE RIVER

SEC 25 PINE RIVER TWP, Gratiot, MI

Built 1987 Load: 35.0 t ADT: 1,058

ROOSEVELT ROAD

Good

Over: DRAIN #49

SEC 18-19 FULTON TWP, Gratiot, MI

Built 1984 Load: 35.3 t ADT: 46

S COUNTY LINE ROAD

Good

Over: FERDON DRAIN

SEC 33 WASHINGTON TWP, Gratiot, MI

Built 1988 Load: 35.3 t ADT: 139

M-46

Good

Over: SUGAR CREEK

2.3 MI W OF ST LOUIS, Gratiot, MI

Built 2002 Load: 36.0 t ADT: 9,986

RANSOM ROAD

Good

Over: DRAIN #192

SEC 21 ELBA TWP, Gratiot, MI

Built 1992 Load: 36.0 t ADT: 69

LUCE ROAD

Good

Over: DRAIN #1

SEC 28-29 NEWARK TWP, Gratiot, MI

Built 1987 Load: 36.4 t ADT: 113

WASHINGTON ROAD

Good

Over: SHAD CREEK DRAIN EXT.

SEC 34 LAFAYETTE TWP, Gratiot, MI

Built 1955 Load: 36.6 t ADT: 667

RANSOM ROAD

Good

Over: MAPLE RIVER

SEC 20-21 ELBA TWP, Gratiot, MI

Built 1985 Load: 36.6 t ADT: 71

TAFT ROAD

Good

Over: DRAIN #49

SEC 19-30 FULTON TWP, Gratiot, MI

Built 2016 Load: 37.3 t ADT: 114

LUCE ROAD

Good

Over: PINE CREEK

SEC 20-21 FULTON TWP, Gratiot, MI

Built 1987 Load: 38.6 t ADT: 975

HARRISON ROAD

Good

Over: PINE RIVER

SEC 8-17 ARCADA TWP, Gratiot, MI

Built 1977 Load: 38.7 t ADT: 1,020

MICHIGAN AVE

Good

Over: HORSE CREEK

CITY OF ST LOUIS, Gratiot, MI

Built 1994 Load: 38.7 t ADT: 5,068

N COUNTY LINE ROAD

Good

Over: PINE RIVER

SEC 3 BETHANY TWP, Gratiot, MI

Built 1985 Load: 38.8 t ADT: 77

M-46

Good

Over: W BR PINE RIVER

2.1 MI W OF US 27, Gratiot, MI

Built 2006 Load: 39.2 t ADT: 6,570

JACKSON ROAD

Good

Over: DRAIN #73

SEC 30-31 PINE RIVER TWP, Gratiot, MI

Built 1985 Load: 39.6 t ADT: 211

MASON ROAD

Good

Over: POTATO CREEK DRAIN

SEC 1-2 HAMILTON TWP, Gratiot, MI

Built 1994 Load: 39.7 t ADT: 77

LUCE ROAD

Good

Over: NORTH END DRAIN

SEC 16-17 ARCADA TWP, Gratiot, MI

Built 1988 Load: 40.8 t ADT: 2,590

GRENDLUND ROAD

Good

Over: MAPLE RIVER

SEC 21-28 ELBA TWP, Gratiot, MI

Built 1990 Load: 40.9 t ADT: 116

M-57

Good

Over: BEAR CREEK

3.5 MI E OF US 27, Gratiot, MI

Built 2011 Load: 41.1 t ADT: 3,942

US-127 SB

Good

Over: MAPLE RIVER

1.5 MI N OF CLINTON COL, Gratiot, MI

Built 1955 Load: 43.4 t ADT: 10,831

CRAPO ROAD

Good

Over: BEAR CREEK

SEC 2-3 WASHINGTON TWP, Gratiot, MI

Built 1995 Load: 45.4 t ADT: 76

TAFT ROAD

Good

Over: OTTER CREEK

FULTON TWP SEC 19, Gratiot, MI

Built 2012 Load: 46.7 t ADT: 92

ST CHARLES ROAD

Good

Over: BAD RIVER

SEC 26-35 LAFAYETTE TWP, Gratiot, MI

Built 1990 Load: 46.9 t ADT: 144

JACKSON ROAD

Good

Over: PINE RIVER

SEC 30 SEVILLE TWP, Gratiot, MI

Built 1991 Load: 47.3 t ADT: 1,145

LUCE ROAD

Good

Over: PINE CREEK

SEC 32-33 NEWARK TWP, Gratiot, MI

Built 1991 Load: 47.9 t ADT: 171

ELY HIGHWAY

Good

Over: DRAIN #163

SEC 30 FULTON TWP, Gratiot, MI

Built 1990 Load: 48.2 t ADT: 1,445

MCCLELLAND ROAD

Good

Over: BAD RIVER DRAIN

SEC 7-8 HAMILTON TWP, Gratiot, MI

Built 1999 Load: 48.9 t ADT: 139

LUMBER JACK ROAD

Good

Over: PINE RIVER

SEC 6 SUMNER TWP, Gratiot, MI

Built 1949 Load: 51.8 t ADT: 915

ROOSEVELT ROAD

Good

Over: DRAIN #140

SEC 24 ELBA TWP, Gratiot, MI

Built 1991 Load: 51.9 t ADT: 139

MILL STREET

Good

Over: PINE RIVER

CITY OF ST LOUIS, Gratiot, MI

Built 1979 Load: 53.8 t ADT: 2,700

OLIVE ROAD

Good

Over: BUSH CREEK DRAIN

SEC 25 BETHANY TWP, Gratiot, MI

Built 2015 Load: 54.4 t ADT: 86

Read our methodology - how this data is sourced, computed, and verified.

Related

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.