Total bridges
167
Public highway bridges in Gratiot County
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.
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
- 1900s 3
1900–1909
3 bridges
- 1910s 1
1910–1919
1 bridges
- 1920s 4
1920–1929
4 bridges
- 1930s 10
1930–1939
10 bridges
- 1940s 4
1940–1949
4 bridges
- 1950s
1950–1959
15 bridges
- 1960s
1960–1969
29 bridges
- 1970s
1970–1979
21 bridges
- 1980s
1980–1989
34 bridges
- 1990s
1990–1999
19 bridges
- 2000s
2000–2009
14 bridges
- 2010s 12
2010–2019
12 bridges
- 2020s 1
2020–2029
1 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).
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.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Sanilac County | 171 | 31.6% | 58.5% | 9.9% | 1978 |
| Gratiot County (this page) | 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 |
| Lapeer County | 163 | 36.2% | 54.6% | 9.2% | 1982 |
| Shiawassee County | 163 | 45.4% | 45.4% | 9.2% | 1981 |
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).
- Cherokee County, AL · 167 bridges
- Garfield County, CO · 167 bridges
- Mitchell County, IA · 167 bridges
- Ness County, KS · 167 bridges
Similar average build year
Nearest mean year-built outside MI (1975 here).
- San Bernardino County, CA · avg 1975 · 1,422 bridges
- Lane County, OR · avg 1975 · 1,010 bridges
- Fulton County, GA · avg 1975 · 775 bridges
- Westmoreland County, PA · avg 1975 · 620 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (79)
POLK ROAD
FairOver: PINE RIVER
SEC 24-25 SUMNER TWP, Gratiot, MI
Built 1983 Load: 39.1 t ADT: 114
BARRY ROAD
FairOver: SHAD CREEK DRAIN EXTN
SEC 33-34 LAFAYETTE TWP, Gratiot, MI
Built 1957 Load: 39.5 t ADT: 1,210
MADISON ROAD
FairOver: PINE RIVER
SEC 18-19 SEVILLE TWP, Gratiot, MI
Built 1989 Load: 39.7 t ADT: 125
US-127 SB
FairOver: US-127 BR
1.0 MI E OF ITHACA, Gratiot, MI
Built 1959 Load: 39.9 t ADT: 8,987
BLAIR ROAD
FairOver: MAPLE RIVER
SEC. 25-26 WASHINGTON TWP, Gratiot, MI
Built 1967 Load: 39.9 t ADT: 330
M-57
FairOver: PINE CRK
5.8 MI W OF US 27, Gratiot, MI
Built 2000 Load: 40.5 t ADT: 4,385
US-127 NB
FairOver: US-127 BR
1.0 MI E OF ITHACA, Gratiot, MI
Built 1959 Load: 40.8 t ADT: 8,987
VAN BUREN RD
FairOver: US-127 NB / MID MI PATH
5.0 MI N OF ITHACA, Gratiot, MI
Built 1965 Load: 41.1 t ADT: 475
US-127 NB
FairOver: N BR BAD RIVER
5.3 MI SE OF ITHACA, Gratiot, MI
Built 1987 Load: 41.5 t ADT: 9,134
STATE ROAD
FairOver: BEAR CREEK DRAIN
SEC 31 NORTH STAR TWP, Gratiot, MI
Built 1984 Load: 41.5 t ADT: 1,020
JOHNSON ROAD
FairOver: DRAIN #1
SEC 21-28 NEWARK TWP, Gratiot, MI
Built 1982 Load: 42.6 t ADT: 113
ST CHARLES ROAD
FairOver: PINE RIVER
SEC 29-32 SUMNER TWP, Gratiot, MI
Built 1967 Load: 42.7 t ADT: 665
US-127 NB
FairOver: MAPLE RIVER
1.5 MI N OF CLINTON COL, Gratiot, MI
Built 1988 Load: 42.8 t ADT: 10,831
MADISON ROAD
FairOver: BUSH CREEK DRAIN
SEC 14-23 BETHANY TWP, Gratiot, MI
Built 1957 Load: 43.5 t ADT: 71
BUCHANAN ROAD
FairOver: DRAIN #294
SEC 16-21 NORTH STAR TWP, Gratiot, MI
Built 1952 Load: 45.0 t ADT: 910
M-57
FairOver: US-127
WASHINGTON TWP SEC 8 & 17, Gratiot, MI
Built 2000 Load: 45.7 t ADT: 3,900
BLAIR ROAD
FairOver: BAD RIVER DRAIN
SEC 13-14 NORTH STAR TWP, Gratiot, MI
Built 1978 Load: 46.9 t ADT: 114
WEST CENTER STREET
FairOver: TUSCOLA & SAGINAW BAY RR
CITY OF ITHACA, Gratiot, MI
Built 1990 Load: 48.6 t ADT: 4,222
US-127 SB
FairOver: US-127 BR
1.5 MI S OF ST LOUIS, Gratiot, MI
Built 1961 Load: 48.9 t ADT: 15,400
US-127 SB
FairOver: MID MICHIGAN RR
0.5 MI S OF ST LOUIS, Gratiot, MI
Built 1960 Load: 49.9 t ADT: 8,293
US-127 NB
FairOver: US-127 BR
1.5 MI S OF ST LOUIS, Gratiot, MI
Built 1961 Load: 50.2 t ADT: 15,400
M-46
FairOver: BUSH CREEK
3.5 MI E OF ST LOUIS, Gratiot, MI
Built 1960 Load: 51.2 t ADT: 5,784
M-46
FairOver: PINE RIVER
0.6 MI E OF COUNTY LINE, Gratiot, MI
Built 1936 Load: 52.2 t ADT: 5,634
BLAIR ROAD
FairOver: BUSH CREEK DRAIN
SEC 13-14 BETHANY TWP, Gratiot, MI
Built 1996 Load: 52.4 t ADT: 375
BLAIR ROAD
FairOver: BUSH CREEK DRAIN
SEC 13-14 BETHANY TWP, Gratiot, MI
Built 1996 Load: 55.0 t ADT: 375
WILSON ROAD
FairOver: GRILL & CONE DRAIN
SEC 29-32 NORTH SHADE TWP, Gratiot, MI
Built 1978 Load: 63.5 t ADT: 170
M-57
FairOver: COUNTY DRAIN
1.0 MI SE OF ASHLEY, Gratiot, MI
Built 1939 Load: 64.8 t ADT: 3,942
LINCOLN ROAD
FairOver: BEAVER CREEK
SEC 35 WHEELER TWP, Gratiot, MI
Built 1962 Load: 70.0 t ADT: 1,300
JOHNSON ROAD
FairOver: RIVER STYX DRAIN
SEC 20-29 NEWARK TWP, Gratiot, MI
Built 1900 Load: 78.9 t ADT: 111
Read our methodology - how this data is sourced, computed, and verified.
Related
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.