County profile · official public datasets

Johnson County, IN

230 public highway bridges tracked in the FHWA National Bridge Inventory: 41.3% rated Good, 50.4% Fair, 8.3% Poor.

230
Public bridges: 41.3%
Good condition: 8.3%
Poor condition

The verdict

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

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

77th
of 92 on Poor share: 8.3%
Poor-condition share: 230
public highway bridges: 1983
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.

Johnson County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Johnson County ranks #77 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.3%). Johnson County, Indiana contains 230 public highway bridges. Roughly 41.3% are rated “Good,” 50.4% “Fair,” and 8.3% “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

230

Public highway bridges in Johnson County

Good condition

41.3%

95 of 230 rated 7-9

Fair condition

50.4%

116 of 230 rated 5-6

Poor condition

8.3%

19 of 230 rated 4 or below

In-state Poor-share rank

#77 of 92

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

Condition distribution

Share of 230 NBI-tracked bridges by lowest applicable component rating.

Good

41.3% (95)

Fair

50.4% (116)

Poor

8.3% (19)

Johnson County's Poor-condition bridges carry 37,360 vehicle crossings a day

That is 2.4% of the county's reported daily bridge traffic on 8.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,966 crossings a day against 10,206 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 230 of 230 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

33.9% of Johnson County's bridges have passed the 50-year mark

78 of the 230 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 41.3% 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 48.2% of the county's Poor-condition bridge traffic

SMITH VALLEY ROAD over CONRAIL RAILROAD, built 1972, carries 18,020 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 19-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 37,360 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

2
1910s

1
1920s

2
1930s

3
1940s

11
1950s

9
1960s

22
1970s

49
1980s

34
1990s

33
2000s

32
2010s

14
2020s

18

What this shows Construction peaked in the 1970s, when 49 of the county's bridges still in the inventory were built, which is 21.3% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1983, 5 years newer than the Indiana average of 1978.

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

The 5 Indiana counties nearest Johnson County in number of bridges, with their condition splits. Its 8.3% Poor share is the 5th-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1978 is 5 years newer.

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

Bridge inventory size and condition shares for Johnson County and the 5 Indiana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Greene County	239	43.9%	46.9%	9.2%	1982
Monroe County	232	62.1%	35.8%	2.2%	1988
Johnson County (this page)	230	41.3%	50.4%	8.3%	1983
LaPorte County	227	33.5%	59.9%	6.6%	1972
Rush County	227	25.6%	70.5%	4%	1970
St. Joseph County	227	49.8%	45.4%	4.8%	1980

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

Similar inventory size

Nearest county inventories outside IN (230 bridges here).

Clark County, IL · 230 bridges
Saline County, MO · 230 bridges
Greer County, OK · 230 bridges
Saline County, AR · 231 bridges

Similar average build year

Nearest mean year-built outside IN (1983 here).

Dallas County, TX · avg 1983 · 3,230 bridges
Bexar County, TX · avg 1983 · 2,342 bridges
Sedgwick County, KS · avg 1983 · 1,333 bridges
Will County, IL · avg 1983 · 649 bridges

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

All 230 Good 95 Fair 116 Poor 19

Good-condition bridges (95)

Sort:

Johnson County Bridge Snapshot

Condition distribution

Johnson County's Poor-condition bridges carry 37,360 vehicle crossings a day

33.9% of Johnson County's bridges have passed the 50-year mark

One structure carries 48.2% of the county's Poor-condition bridge traffic

How Johnson 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 (95)

NB MADISON AVENUE

HOME AVENUE

US 31 NB

US 31 SB

I-65 SB

SR 37 SBL ON RAMP

HOSPITAL ROAD

CR 500 SOUTH

I-65 SB

SR 37 NBL OFF RAMP

SR 37 SBL

I-65 SB

MORGANTOWN RD

CENTERLINE ROAD

SR 37 SB

FRY ROAD

SB MADISON AVENUE

US 31

GREENSBURG ROAD

CHERRY TREE LANE

GOLDEN GROVE ROAD

I-65 NB

I-65 SB

SR 44

SR 37 NB/SB

CR 200 SOUTH

HONEY CREEK RD

E WORTHSVILLE ROAD

SR 37 NBL

E WORTHSVILLE ROAD

SR 135

SR 135

CR 600 EAST

SR-144

MAIN STREET

SR 37 SB

SR 37 NB & RAMP

WEST SERVICE ROAD

CR 775 WEST

CENTER STREET

EAGLE TRACE DRIVE

MAIN STREET

SR 44

SR 135

SR 135

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