County profile · official public datasets

Knox County, MO

167 public highway bridges tracked in the FHWA National Bridge Inventory: 34.7% rated Good, 61.1% Fair, 4.2% Poor.

167
Public bridges: 34.7%
Good condition: 4.2%
Poor condition

The verdict

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

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

Top 12%
lowest Poor share in state: 4.2%
Poor-condition share: 167
public highway bridges: 1987
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.

Knox County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Knox County ranks #14 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.2%). Knox County, Missouri contains 167 public highway bridges. Roughly 34.7% are rated “Good,” 61.1% “Fair,” and 4.2% “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

167

Public highway bridges in Knox County

Good condition

34.7%

58 of 167 rated 7-9

Fair condition

61.1%

102 of 167 rated 5-6

Poor condition

4.2%

7 of 167 rated 4 or below

In-state Poor-share rank

#14 of 115

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

Condition distribution

Share of 167 NBI-tracked bridges by lowest applicable component rating.

Good

34.7% (58)

Fair

61.1% (102)

Poor

4.2% (7)

Knox County's Poor-condition bridges carry 1,294 vehicle crossings a day

That is 3.5% of the county's reported daily bridge traffic on 4.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 185 crossings a day against 101 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 167 of 167 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

22.8% of Knox County's bridges have passed the 50-year mark

38 of the 167 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 34.7% 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 71.4% of the county's Poor-condition bridge traffic

RT V S over LIT BRIDGES CR, built 1951, carries 924 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 7-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,294 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

5
1930s

10
1940s

2
1950s

12
1960s

7
1970s

2
1980s

23
1990s

44
2000s

46
2010s

15
2020s

1

What this shows Construction peaked in the 2000s, when 46 of the county's bridges still in the inventory were built, which is 27.5% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year is 1987, 8 years newer than the Missouri average of 1979.

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

The 5 Missouri counties nearest Knox County in number of bridges, with their condition splits. Its 4.2% Poor share is the 1st-lowest of these 6. Its average build year of 1987 against a peer-group mean of 1977 is 10 years newer.

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

Bridge inventory size and condition shares for Knox County and the 5 Missouri counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Lewis County	171	28.7%	66.1%	5.3%	1990
Holt County	167	38.3%	46.7%	15%	1974
Knox County (this page)	167	34.7%	61.1%	4.2%	1987
Barry County	166	23.5%	61.4%	15.1%	1973
St. Francois County	165	38.2%	51.5%	10.3%	1968
Montgomery County	163	28.8%	65%	6.1%	1979

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

Similar inventory size

Nearest county inventories outside MO (167 bridges here).

Cherokee County, AL · 167 bridges
Garfield County, CO · 167 bridges
Mitchell County, IA · 167 bridges
Ness County, KS · 167 bridges

Similar average build year

Nearest mean year-built outside MO (1987 here).

Ellis County, TX · avg 1987 · 691 bridges
St. Louis County, MN · avg 1987 · 663 bridges
Palm Beach County, FL · avg 1987 · 610 bridges
Dane County, WI · avg 1987 · 590 bridges

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

All 167 Good 58 Fair 102 Poor 7

All bridges (167)

Sort:

COUNTY RD 412

Fair

Over: BRANCH

S 5 T 62 N R 12 W, Knox, MO

Built 2001 Load: 99.9 t ADT: 20

COUNTY RD 025

Fair

Over: BR N FK S FABIUS R

S 8 T 63 N R 12 W, Knox, MO

Knox County Bridge Snapshot

Condition distribution

Knox County's Poor-condition bridges carry 1,294 vehicle crossings a day

22.8% of Knox County's bridges have passed the 50-year mark

One structure carries 71.4% of the county's Poor-condition bridge traffic

How Knox 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

All bridges (167)

COUNTY RD 412

COUNTY RD 025

RT K E

COUNTY RD 183

CITY ST 131

MO 156 E

COUNTY RD 150

COUNTY RD 230

COUNTY RD 289

COUNTY RD 347

COUNTY RD 144

COUNTY RD 281

COUNTY RD 181

COUNTY RD 324

RT E N

COUNTY RD 206

COUNTY RD 372

COUNTY RD 375

RT M S

MO 156 E

COUNTY RD 92

COUNTY RD 164

COUNTY RD 183

COUNTY RD 271

COUNTY RD 344

RT E S

COUNTY RD 135

MO 151 S

COUNTY RD 090

MO 15 N

COUNTY RD 187

COUNTY RD 166

COUNTY RD 370

COUNTY RD 162

COUNTY RD 219

COUNTY RD 179

COUNTY RD 297

COUNTY RD 312

COUNTY RD 349

COUNTY RD 385

COUNTY RD 004

COUNTY RD 298

COUNTY RD 24

COUNTY RD 84

COUNTY RD 161

COUNTY RD 220

COUNTY RD 338

COUNTY RD 378

COUNTY RD 129

COUNTY RD 387

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