County profile · official public datasets

Johnson County, MO

476 public highway bridges tracked in the FHWA National Bridge Inventory: 39.3% rated Good, 56.3% Fair, 4.4% Poor.

476
Public bridges: 39.3%
Good condition: 4.4%
Poor condition

The verdict

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

Johnson County posts a top-quartile lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 14%
lowest Poor share in state: 4.4%
Poor-condition share: 476
public highway bridges: 1975
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 #16 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.4%). Johnson County, Missouri contains 476 public highway bridges. Roughly 39.3% are rated “Good,” 56.3% “Fair,” and 4.4% “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

476

Public highway bridges in Johnson County

Good condition

39.3%

187 of 476 rated 7-9

Fair condition

56.3%

268 of 476 rated 5-6

Poor condition

4.4%

21 of 476 rated 4 or below

In-state Poor-share rank

#16 of 115

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

Condition distribution

Share of 476 NBI-tracked bridges by lowest applicable component rating.

Good

39.3% (187)

Fair

56.3% (268)

Poor

4.4% (21)

Johnson County's Poor-condition bridges carry 18,285 vehicle crossings a day

That is 4.1% of the county's reported daily bridge traffic on 4.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 871 crossings a day against 642 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 476 of 476 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

30.7% of Johnson County's bridges have passed the 50-year mark

146 of the 476 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 39.3% 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 45.6% of the county's Poor-condition bridge traffic

US 50 E over UP RR, built 1968, carries 8,346 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 21-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 18,285 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

84
1910s

3
1920s

10
1930s

6
1940s

2
1950s

20
1960s

19
1970s

5
1980s

43
1990s

151
2000s

78
2010s

52
2020s

3

What this shows Construction peaked in the 1990s, when 151 of the county's bridges still in the inventory were built, which is 31.7% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1975) matches the Missouri average (1979).

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

The 5 Missouri counties nearest Johnson County in number of bridges, with their condition splits. Its 4.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1975 against a peer-group mean of 1981 is 6 years older.

Showing the 5 closest of 114 Missouri counties eligible for comparison.

Bridge inventory size and condition shares for Johnson County and the 5 Missouri counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Greene County	493	44.6%	50.1%	5.3%	1978
Johnson County (this page)	476	39.3%	56.3%	4.4%	1975
Jasper County	471	42%	46.9%	11%	1978
Clay County	436	38.1%	55%	6.9%	1979
Stoddard County	434	43.1%	53.2%	3.7%	1976
St. Charles County	417	32.4%	64.3%	3.4%	1994

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 Missouri so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside MO (476 bridges here).

Grant County, OK · 476 bridges
Providence County, RI · 476 bridges
Tangipahoa County, LA · 477 bridges
Kiowa County, OK · 477 bridges

Similar average build year

Nearest mean year-built outside MO (1975 here).

San Bernardino County, CA · avg 1975 · 1,422 bridges
Lane County, OR · avg 1975 · 1,010 bridges
Fulton County, GA · avg 1975 · 775 bridges
Westmoreland County, PA · avg 1975 · 620 bridges

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

All 476 Good 187 Fair 268 Poor 21

Good-condition bridges (187)

Sort:

Johnson County Bridge Snapshot

Condition distribution

Johnson County's Poor-condition bridges carry 18,285 vehicle crossings a day

30.7% of Johnson County's bridges have passed the 50-year mark

One structure carries 45.6% of the county's Poor-condition bridge traffic

How Johnson County compares with Missouri'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 (187)

CO RD NW 450

CO RD 871

CO RD NW 701

CO RD SW 1151

CO RD NW 675

MO 23 S

CO RD NW 400

CO RD NW 750

CO RD NW 400

RT CC S

COUNTY RD NW 1901

RT WW S

CO RD NE 925

CO RD SW 1541

CO RD SW 650

E DIVISION RD

RT E E

CO RD N W 1021

CO RD NE 1000

COUNTY RD NW 100

RT B S

RT ZZ S

CO RD SW 1101

CO RD NE 421

CO RD SW 800

CO RD SE 775

CO RD SW 301

CO RD NW 1151

COUNTY RD SW 800

MO 13 S

CO RD NW 150

CO RD SW 971

CO RD 151

US 50 E

RT E E

RT PP E

AMMO AVENUE

CO RD 121

CO RD SW 970

CO RD NW501

CO RD NW 1971

COUNTY RD NW 600

US 50 W

MO 2 E

RT DD E

CO RD SW 701

US 50 E

MO 2 E

MO 2 E

US 50 W

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