Total bridges
166
Public highway bridges in Bay County
County profile · official public datasets
Bay County, MI
166 public highway bridges tracked in the FHWA National Bridge Inventory: 30.1% rated Good, 53% Fair, 16.9% Poor.
- 166
- Public bridges
- 30.1%
- Good condition
- 16.9%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Bay County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- 66th
- of 83 on Poor share
- 16.9%
- Poor-condition share
- 166
- public highway bridges
- 1974
- 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.
Bay County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Bay County ranks #66 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 16.9%). Bay County, Michigan contains 166 public highway bridges. Roughly 30.1% are rated “Good,” 53% “Fair,” and 16.9% “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
30.1%
50 of 166 rated 7-9
Fair condition
53%
88 of 166 rated 5-6
Poor condition
16.9%
28 of 166 rated 4 or below
In-state Poor-share rank
#66 of 83
Among Michigan counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 166 NBI-tracked bridges by lowest applicable component rating.
Good 30.1% (50)
Fair 53% (88)
Poor 16.9% (28)
Bay County's Poor-condition bridges carry 64,301 vehicle crossings a day
That is 5.9% of the county's reported daily bridge traffic on 16.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 2,296 crossings a day against 8,156 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 166 of 166 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
60.8% of Bay County's bridges have passed the 50-year mark
101 of the 166 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 30.1% 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 28.9% of the county's Poor-condition bridge traffic
I-75 NB over HESR, built 1960, carries 18,568 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 28-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 64,301 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Bay County's bridges were built
166 bridges with a recorded construction year, grouped by decade
- 1920s 3
1920–1929
3 bridges
- 1930s 18
1930–1939
18 bridges
- 1940s 5
1940–1949
5 bridges
- 1950s 16
1950–1959
16 bridges
- 1960s
1960–1969
47 bridges
- 1970s 18
1970–1979
18 bridges
- 1980s 11
1980–1989
11 bridges
- 1990s 14
1990–1999
14 bridges
- 2000s 13
2000–2009
13 bridges
- 2010s 13
2010–2019
13 bridges
- 2020s 8
2020–2029
8 bridges
What this shows Construction peaked in the 1960s, when 47 of the county's bridges still in the inventory were built, which is 28.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1974) matches the Michigan average (1976).
How Bay County compares with Michigan's closest counties by inventory size
The 5 Michigan counties nearest Bay County in number of bridges, with their condition splits. Its 16.9% Poor share is the 6th-lowest of these 6. Its average build year of 1974 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 | 167 | 40.7% | 47.3% | 12% | 1975 |
| Bay County (this page) | 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 Bay 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 Bay County, both outside Michigan so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MI (166 bridges here).
- Clay County, IL · 166 bridges
- Trego County, KS · 166 bridges
- Pontotoc County, MS · 166 bridges
- Barry County, MO · 166 bridges
Similar average build year
Nearest mean year-built outside MI (1974 here).
- Knox County, TN · avg 1974 · 588 bridges
- Summit County, OH · avg 1974 · 563 bridges
- Onondaga County, NY · avg 1974 · 472 bridges
- Orange County, NY · avg 1974 · 472 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (88)
BROWN ROAD
FairOver: CONSTANT DURUSSEL DRAIN
AT BRIGGS RD, Bay, MI
Built 1948 Load: 4.5 t ADT: 121
SAGANING ROAD
FairOver: SAGANING CREEK
0.25 MI E OF NINE MILE, Bay, MI
Built 1938 Load: 13.3 t ADT: 569
GARFIELD ROAD
FairOver: WHITE FEATHER CREEK
0.5 MI N OF W CODY ESTEY, Bay, MI
Built 1959 Load: 14.6 t ADT: 50
ARMS ROAD
FairOver: VAN WERT DRAIN
AT N FINN ROAD, Bay, MI
Built 1956 Load: 15.6 t ADT: 50
WOODSIDE AVE
FairOver: SAGINAW RIVER AND MCRR
BAY CITY, Bay, MI
Built 1987 Load: 19.4 t ADT: 19,300
TOWER BEACH ROAD
FairOver: JOHNSONS CREEK
200 FT N OF ALMEDA BEACH, Bay, MI
Built 1975 Load: 19.6 t ADT: 457
TOWER BEACH ROAD
FairOver: TEBO DRAIN
AT COGGINS RD, Bay, MI
Built 1972 Load: 19.6 t ADT: 470
MACKINAW RD
FairOver: PINCONNING RIVER
0.2 MI S OF PINCONNING RD, Bay, MI
Built 1925 Load: 21.7 t ADT: 676
BEAVER ROAD
FairOver: WALDO DRAIN
500 FT W OF ELEVEN MI RD, Bay, MI
Built 1932 Load: 23.0 t ADT: 1,075
BEAVER ROAD
FairOver: KAWKAWLIN RIVER
200 FT W OF FOUR MILE RD, Bay, MI
Built 1928 Load: 23.0 t ADT: 3,404
COTTER ROAD
FairOver: QUANICASSEE RIVER
3/8 MI N OF MUNGER RD, Bay, MI
Built 1975 Load: 24.3 t ADT: 87
FRASER ROAD
FairOver: KAWKAWLIN RIVER
0.6 MI N OF N UNION RD, Bay, MI
Built 1986 Load: 24.5 t ADT: 366
RUSSELL ROAD
FairOver: QUANICASSEE RIVER
0.25 MI E OF COTTER RD, Bay, MI
Built 1971 Load: 25.9 t ADT: 106
M-13
FairOver: WHITE FEATHER CREEK
3.0 MI N OF PINCONNING, Bay, MI
Built 1938 Load: 27.5 t ADT: 8,300
NINE MILE ROAD
FairOver: N BR KAWKAWLIN RIVER
0.2 MI N OF PARISH RD, Bay, MI
Built 1980 Load: 28.1 t ADT: 350
SEVEN MILE RD
FairOver: US-10
6.0 MI W OF BAY CITY, Bay, MI
Built 1958 Load: 29.5 t ADT: 1,869
ZIEGLER ROAD
FairOver: DUTCH CREEK
0.1 MI S OF M-84, Bay, MI
Built 1971 Load: 29.8 t ADT: 393
MAIDA ROAD
FairOver: M BR PINE RIVER
0.25 MI N OF M-61, Bay, MI
Built 1970 Load: 29.8 t ADT: 150
BEAVER ROAD
FairOver: KAWKAWLIN RIVER
1 600 FT E OF GARFIELD RD, Bay, MI
Built 1987 Load: 30.1 t ADT: 2,870
TOWNLINE 14 ROAD
FairOver: KAWKAWLIN RIVER
1000 FEET E OF 9 MI RD, Bay, MI
Built 1970 Load: 30.5 t ADT: 66
FRASER ROAD
FairOver: N BR KAWKAWLIN RIVER
AT RIVER RD, Bay, MI
Built 1957 Load: 30.7 t ADT: 279
CARTER RD
FairOver: US-10
1.0 MI W OF FISHERVILLE, Bay, MI
Built 1958 Load: 30.8 t ADT: 900
FLAJOLE RD
FairOver: US-10
1.0 MI E OF MIDLAND COL, Bay, MI
Built 1958 Load: 31.1 t ADT: 739
ELEVEN MILE RD
FairOver: US-10
2.0 MI W OF AUBURN, Bay, MI
Built 1958 Load: 31.1 t ADT: 895
MONITOR ROAD
FairOver: MILL POND DRAIN
0.5 MI S OF KAWKAWLIN, Bay, MI
Built 1972 Load: 31.1 t ADT: 796
PREVO ROAD
FairOver: FRASER-GARFIELD DRAIN
1000 FT WEST OF M-13, Bay, MI
Built 1988 Load: 31.7 t ADT: 671
PINCONNING ROAD
FairOver: PINCONNING RIVER
0.75 MI W OF PINCONNING, Bay, MI
Built 1987 Load: 31.7 t ADT: 5,405
SALZBURG ROAD
FairOver: CULVER CREEK
700 FT W OF EIGHT MILE RD, Bay, MI
Built 1987 Load: 31.7 t ADT: 2,264
BEAVER ROAD
FairOver: WALDO DRAIN
100 FT E OF ELEVEN MI RD, Bay, MI
Built 1992 Load: 32.0 t ADT: 1,557
SEVEN MILE ROAD
FairOver: PINCONNING RIVER
1000 FT N OF NEUMAN RD, Bay, MI
Built 1992 Load: 32.0 t ADT: 1,778
FRASER ROAD
FairOver: TEBO CREEK
AT ERICKSON RD, Bay, MI
Built 1976 Load: 32.0 t ADT: 246
HOTCHKISS ROAD
FairOver: SQUACONNING CREEK
100 FT E OF MACKINAW RD, Bay, MI
Built 1992 Load: 32.3 t ADT: 841
LINWOOD ROAD
FairOver: CRUMP DRAIN
1000 FT E OF GARFIELD RD, Bay, MI
Built 1991 Load: 32.3 t ADT: 2,556
M-13
FairOver: RAILROAD DRAIN
0.4 MI S OF LINWOOD RD, Bay, MI
Built 1950 Load: 32.7 t ADT: 15,061
SEVEN MILE ROAD
FairOver: SAGANING RIVER
1.1 MI S OF WORTH ROAD, Bay, MI
Built 1967 Load: 32.7 t ADT: 50
N UNION RD
FairOver: I-75
3.0 MI S OF KAWKAWLIN, Bay, MI
Built 1961 Load: 33.4 t ADT: 1,045
BAY RD
FairOver: US-10
0.4 MI E OF MIDLAND COL, Bay, MI
Built 1999 Load: 33.4 t ADT: 7,770
AMELITH RD
FairOver: I-75
1.0 MI N OF SAGINAW COL, Bay, MI
Built 1960 Load: 33.7 t ADT: 528
TRUMAN PARKWAY
FairOver: SAGINAW RV;MARTIN ST&RR
IN BAY CITY, Bay, MI
Built 1976 Load: 33.7 t ADT: 21,832
COGGINS RD
FairOver: I-75
3.0 MI SW OF PINCONNING, Bay, MI
Built 1968 Load: 34.0 t ADT: 818
I-75 NB
FairOver: MIDLAND ROAD
3.6 MI S OF KAWKAWLIN, Bay, MI
Built 2001 Load: 34.7 t ADT: 18,568
I-75 SB
FairOver: MIDLAND ROAD
3.6 MI S OF KAWKAWLIN, Bay, MI
Built 2001 Load: 34.7 t ADT: 18,568
M-25
FairOver: SAGINAW RIVER & JFK DR
IN BAY CITY, Bay, MI
Built 1958 Load: 34.7 t ADT: 23,441
SEVEN MILE ROAD
FairOver: KAWKAWLIN RIVER
100 FT S OF WILDER RD, Bay, MI
Built 1961 Load: 35.0 t ADT: 1,200
NINE MILE RD
FairOver: US-10
S LTS OF AUBURN, Bay, MI
Built 2015 Load: 35.3 t ADT: 2,120
ANDERSON ROAD
FairOver: N BR OF KAWKAWLIN RIVER
300 FT W OF FLAJOLE RD, Bay, MI
Built 1961 Load: 35.3 t ADT: 1,415
GARFIELD ROAD
FairOver: N BR KAWKAWLIN RIVER
2 MI S OF CRUMP, Bay, MI
Built 1992 Load: 35.6 t ADT: 1,715
CHIP ROAD
FairOver: N BR KAWKAWLIN RIVER
0.5 MI SW OLD BEAVER RD, Bay, MI
Built 1930 Load: 35.8 t ADT: 438
SALZBURG RD
FairOver: I-75
4.0 MI N OF SAGINAW COL, Bay, MI
Built 1960 Load: 36.6 t ADT: 5,197
I-75 SB
FairOver: WHEELER ROAD
1.7 MI S OF KAWKAWLIN, Bay, MI
Built 1968 Load: 36.6 t ADT: 11,225
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.