Total bridges
230
Public highway bridges in Johnson County
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.
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.
When Johnson County's bridges were built
230 bridges with a recorded construction year, grouped by decade
- pre-1900 2
Built before 1900
2 bridges
- 1910s 1
1910–1919
1 bridges
- 1920s 2
1920–1929
2 bridges
- 1930s 3
1930–1939
3 bridges
- 1940s 11
1940–1949
11 bridges
- 1950s 9
1950–1959
9 bridges
- 1960s
1960–1969
22 bridges
- 1970s
1970–1979
49 bridges
- 1980s
1980–1989
34 bridges
- 1990s
1990–1999
33 bridges
- 2000s
2000–2009
32 bridges
- 2010s 14
2010–2019
14 bridges
- 2020s 18
2020–2029
18 bridges
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.
| 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.
Fair-condition bridges (116)
CR 600 NORTH
FairOver: GRASSY CREEK
0.20 E OF CR 75 W, Johnson, IN
Built 2000 Load: 41.6 t ADT: 4,725
CR 250 S
FairOver: I-65
03.13 S SR 44, Johnson, IN
Built 1970 Load: 42.1 t ADT: 366
CR 400 WEST
FairOver: HONEY CREEK
0.20 N OF CR 600 N, Johnson, IN
Built 1960 Load: 42.2 t ADT: 2,299
US 31 SB
FairOver: YOUNGS CREEK
02.61 S SR 44, Johnson, IN
Built 1946 Load: 42.5 t ADT: 5,321
CR 200 EAST
FairOver: BUCKHART CREEK
0.50 S OF CR 300 S, Johnson, IN
Built 1966 Load: 42.5 t ADT: 3,944
SMITH VALLEY ROAD
FairOver: HONEY CREEK
0.50 E OF SR 37, Johnson, IN
Built 1962 Load: 42.7 t ADT: 9,182
CR 525 EAST
FairOver: LEATHERWOOD CREEK
0.30 S OF CR 1000 N, Johnson, IN
Built 1985 Load: 44.1 t ADT: 75
US 31
FairOver: HIGH BRIDGE CREEK
05.50 N SR 44, Johnson, IN
Built 1946 Load: 44.4 t ADT: 24,701
US 31 NB
FairOver: SUGAR CREEK
00.54 S SR 252, Johnson, IN
Built 1948 Load: 45.7 t ADT: 5,650
US 31 SB
FairOver: SUGAR CREEK
00.54 S SR 252, Johnson, IN
Built 1948 Load: 45.7 t ADT: 5,840
SR 252
FairOver: YOUNGS CREEK
00.65 W US 31, Johnson, IN
Built 1942 Load: 50.0 t ADT: 3,565
CR 575 WEST
FairOver: INDIAN CREEK
0.10 S OF CR 700 S, Johnson, IN
Built 1988 Load: 50.9 t ADT: 477
CR 550 WEST
FairOver: HONEY CREEK
0.30 S OF SMITH VALLEY RD, Johnson, IN
Built 1986 Load: 51.3 t ADT: 605
US 31 NB
FairOver: YOUNGS CREEK
02.61 S SR 44, Johnson, IN
Built 1946 Load: 52.3 t ADT: 5,263
SR 44
FairOver: S PRONG STOTTS CREEK
00.11 W SR 135, Johnson, IN
Built 1987 Load: 53.5 t ADT: 1,660
I-65
FairOver: DRAINAGE DITCH
04.74 N SR 252, Johnson, IN
Built 1969 Load: 97.2 t ADT: 55,807
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.