County profile · official public datasets

Decatur County, IN

220 public highway bridges tracked in the FHWA National Bridge Inventory: 34.5% rated Good, 58.6% Fair, 6.8% Poor.

220
Public bridges: 34.5%
Good condition: 6.8%
Poor condition

The verdict

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

Decatur County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

68th
of 92 on Poor share: 6.8%
Poor-condition share: 220
public highway bridges: 1971
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.

Decatur County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Decatur County ranks #68 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.8%). Decatur County, Indiana contains 220 public highway bridges. Roughly 34.5% are rated “Good,” 58.6% “Fair,” and 6.8% “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

220

Public highway bridges in Decatur County

Good condition

34.5%

76 of 220 rated 7-9

Fair condition

58.6%

129 of 220 rated 5-6

Poor condition

6.8%

15 of 220 rated 4 or below

In-state Poor-share rank

#68 of 92

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

Condition distribution

Share of 220 NBI-tracked bridges by lowest applicable component rating.

Good

34.5% (76)

Fair

58.6% (129)

Poor

6.8% (15)

Decatur County's Poor-condition bridges carry 5,670 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 6.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 378 crossings a day against 1,944 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 220 of 220 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

39.1% of Decatur County's bridges have passed the 50-year mark

86 of the 220 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 34.5% 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 41.4% of the county's Poor-condition bridge traffic

CENTRAL AVE over GAS CREEK, built 1930, carries 2,350 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 5,670 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

21
1910s

5
1920s

11
1930s

9
1940s

3
1950s

3
1960s

26
1970s

33
1980s

17
1990s

45
2000s

26
2010s

12
2020s

9

What this shows Construction peaked in the 1990s, when 45 of the county's bridges still in the inventory were built, which is 20.5% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year is 1971, 7 years older than the Indiana average of 1978.

How Decatur County compares with Indiana's closest counties by inventory size

The 5 Indiana counties nearest Decatur County in number of bridges, with their condition splits. Its 6.8% Poor share is the 6th-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1978 is 7 years older.

Showing the 5 closest of 91 Indiana counties eligible for comparison.

Bridge inventory size and condition shares for Decatur County and the 5 Indiana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
LaPorte County	227	33.5%	59.9%	6.6%	1972
Daviess County	221	59.3%	40.7%	0%	1993
Dubois County	220	49.5%	47.3%	3.2%	1982
Decatur County (this page)	220	34.5%	58.6%	6.8%	1971
Sullivan County	217	29.5%	65.4%	5.1%	1966
White County	214	36%	60.3%	3.7%	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 Decatur 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 Decatur County, both outside Indiana so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IN (220 bridges here).

Bibb County, GA · 220 bridges
Taylor County, IA · 220 bridges
Winn County, LA · 220 bridges
Thayer County, NE · 220 bridges

Similar average build year

Nearest mean year-built outside IN (1971 here).

Wayne County, MI · avg 1971 · 1,026 bridges
Baltimore County, MD · avg 1971 · 783 bridges
Washington County, PA · avg 1971 · 655 bridges
Linn County, OR · avg 1971 · 566 bridges

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

All 220 Good 76 Fair 129 Poor 15

Fair-condition bridges (129)

Sort:

Decatur County Bridge Snapshot

Condition distribution

Decatur County's Poor-condition bridges carry 5,670 vehicle crossings a day

39.1% of Decatur County's bridges have passed the 50-year mark

One structure carries 41.4% of the county's Poor-condition bridge traffic

How Decatur County compares with Indiana's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (129)

LAYTON DR

CR 600S

CR 580W

CR NE 80

CR 700W

I-74 EB

CR 100 W

CR 600E

I-74 WB

CR 820S

CR 850S

CR 200S

SR 3

CR 850E

CR 550N

CR 400S

CR 150W

CR 100W

CR 300S

CR 450W

POPLAR ST

I-74 WBL

CR 150W

CR 400S

I-74 WB

CR 850S

CR 1000S

CR 300W

BASE ROAD

CR 1250S

CR 700W

BASE RD

CR 250S

CR 300S

US 421

NEW POINT-ROSSB RD

CR 640N

CR 600S

CR 200S

CR 650W

CR 650N

CR 400N

CR 400N

CR 300N

CR 100W

CR 300N

CR 1000E

BASE RD

CR 60E

CR 250E

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