County profile · official public datasets

Carroll County, IN

161 public highway bridges tracked in the FHWA National Bridge Inventory: 37.3% rated Good, 60.2% Fair, 2.5% Poor.

161
Public bridges: 37.3%
Good condition: 2.5%
Poor condition

The verdict

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

Carroll County pairs a top-quartile lowest Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 25%
lowest Poor share in state: 2.5%
Poor-condition share: 161
public highway bridges: 1973
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.

Carroll County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Carroll County ranks #23 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.5%). Carroll County, Indiana contains 161 public highway bridges. Roughly 37.3% are rated “Good,” 60.2% “Fair,” and 2.5% “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

161

Public highway bridges in Carroll County

Good condition

37.3%

60 of 161 rated 7-9

Fair condition

60.2%

97 of 161 rated 5-6

Poor condition

2.5%

4 of 161 rated 4 or below

In-state Poor-share rank

#23 of 92

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

Condition distribution

Share of 161 NBI-tracked bridges by lowest applicable component rating.

Good

37.3% (60)

Fair

60.2% (97)

Poor

2.5% (4)

Carroll County's Poor-condition bridges carry 1,377 vehicle crossings a day

That is 0.6% of the county's reported daily bridge traffic on 2.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 344 crossings a day against 1,941 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 161 of 161 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

43.5% of Carroll County's bridges have passed the 50-year mark

70 of the 161 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 37.3% 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 70.7% of the county's Poor-condition bridge traffic

OLD SR 25 over ROBINSON Branch, built 1939, carries 974 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 4-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,377 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

5
1900s

4
1910s

4
1920s

1
1930s

11
1940s

4
1950s

8
1960s

24
1970s

27
1980s

26
1990s

16
2000s

4
2010s

26
2020s

1

What this shows Construction peaked in the 1970s, when 27 of the county's bridges still in the inventory were built, which is 16.8% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1973, 5 years older than the Indiana average of 1978.

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

The 5 Indiana counties nearest Carroll County in number of bridges, with their condition splits. Its 2.5% Poor share is the 1st-lowest of these 6. Its average build year of 1973 against a peer-group mean of 1976 is in line with the group.

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

Bridge inventory size and condition shares for Carroll County and the 5 Indiana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Lawrence County	165	32.1%	58.2%	9.7%	1981
Jennings County	163	39.9%	50.3%	9.8%	1973
Carroll County (this page)	161	37.3%	60.2%	2.5%	1973
Franklin County	159	34%	58.5%	7.5%	1972
Wells County	158	39.2%	55.1%	5.7%	1978
Jefferson County	153	41.8%	54.2%	3.9%	1977

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

Similar inventory size

Nearest county inventories outside IN (161 bridges here).

Floyd County, KY · 161 bridges
Greenup County, KY · 161 bridges
Dade County, MO · 161 bridges
Howard County, NE · 161 bridges

Similar average build year

Nearest mean year-built outside IN (1973 here).

Jefferson County, AL · avg 1973 · 1,068 bridges
Erie County, NY · avg 1973 · 906 bridges
Davidson County, TN · avg 1973 · 832 bridges
Lancaster County, PA · avg 1973 · 801 bridges

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

All 161 Good 60 Fair 97 Poor 4

Good-condition bridges (60)

Sort:

Carroll County Bridge Snapshot

Condition distribution

Carroll County's Poor-condition bridges carry 1,377 vehicle crossings a day

43.5% of Carroll County's bridges have passed the 50-year mark

One structure carries 70.7% of the county's Poor-condition bridge traffic

How Carroll 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

Good-condition bridges (60)

BICYCLE BRIDGE Rd

CR 600E

CR 325E

CR 1100N

SR 18

US 421

SR 75

CR 850N

CR 925W

CR 150E

US 421

SR 25 NB

SR 25 SB

SR 25 NB

WALNUT STREET

CR 100N

CR 400E

SR 25 NB

SR 25 SB

SR 25 NB

SR 25 SB

CR 500 W

CR 300E

SR 25 SB

CR 250S

CR 50 W

US 421

SR 29

CR 725N

CR 175W

CARROLLTON RD

BICYCLE BRIDGE RD

CR 525W

CR 250S

SR 218

SR 29

CR 550N

SR 25

SR 25

CR 300E

CR 500E

CR 300W

CR 225W

SR 18

CR 800N

CR 225E

CR 300E

CR 700S

SR 25

SR 25

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