Total bridges
167
Public highway bridges in Knox County
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.
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.
When Knox County's bridges were built
167 bridges with a recorded construction year, grouped by decade
- 1920s 5
1920–1929
5 bridges
- 1930s 10
1930–1939
10 bridges
- 1940s 2
1940–1949
2 bridges
- 1950s 12
1950–1959
12 bridges
- 1960s 7
1960–1969
7 bridges
- 1970s 2
1970–1979
2 bridges
- 1980s
1980–1989
23 bridges
- 1990s
1990–1999
44 bridges
- 2000s
2000–2009
46 bridges
- 2010s 15
2010–2019
15 bridges
- 2020s 1
2020–2029
1 bridges
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.
| 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.
Fair-condition bridges (102)
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.