County profile · official public datasets

Knox County, IN

290 public highway bridges tracked in the FHWA National Bridge Inventory: 40% rated Good, 55.2% Fair, 4.8% Poor.

290
Public bridges: 40%
Good condition: 4.8%
Poor condition

The verdict

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

Knox County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

47th
of 92 on Poor share: 4.8%
Poor-condition share: 290
public highway bridges: 1976
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 #47 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.8%). Knox County, Indiana contains 290 public highway bridges. Roughly 40% are rated “Good,” 55.2% “Fair,” and 4.8% “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

290

Public highway bridges in Knox County

Good condition

40%

116 of 290 rated 7-9

Fair condition

55.2%

160 of 290 rated 5-6

Poor condition

4.8%

14 of 290 rated 4 or below

In-state Poor-share rank

#47 of 92

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

Condition distribution

Share of 290 NBI-tracked bridges by lowest applicable component rating.

Good

40% (116)

Fair

55.2% (160)

Poor

4.8% (14)

Knox County's Poor-condition bridges carry 1,712 vehicle crossings a day

That is 0.3% of the county's reported daily bridge traffic on 3.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 171 crossings a day against 2,635 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 286 of 290 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

45.5% of Knox County's bridges have passed the 50-year mark

132 of the 290 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 40% 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 43.8% of the county's Poor-condition bridge traffic

TR 257 over WABASH RIVER, built 1906, carries 750 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 14-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,712 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

1
1900s

9
1910s

2
1920s

11
1930s

10
1940s

16
1950s

14
1960s

43
1970s

34
1980s

38
1990s

63
2000s

24
2010s

14
2020s

11

What this shows Construction peaked in the 1990s, when 63 of the county's bridges still in the inventory were built, which is 21.7% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1976) matches the Indiana average (1978).

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

The 5 Indiana counties nearest Knox County in number of bridges, with their condition splits. Its 4.8% Poor share is the 5th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1973 is in line with the group.

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

Bridge inventory size and condition shares for Knox County and the 5 Indiana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Madison County	301	44.5%	52.5%	3%	1978
Vigo County	296	44.9%	50.7%	4.4%	1977
Boone County	293	39.9%	55.3%	4.8%	1974
Putnam County	290	30.3%	51%	18.6%	1963
Knox County (this page)	290	40%	55.2%	4.8%	1976
Grant County	280	38.6%	59.6%	1.8%	1975

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

Similar inventory size

Nearest county inventories outside IN (290 bridges here).

Monroe County, MS · 290 bridges
Yellowstone County, MT · 290 bridges
Outagamie County, WI · 290 bridges
Scott County, IA · 291 bridges

Similar average build year

Nearest mean year-built outside IN (1976 here).

Mohave County, AZ · avg 1976 · 641 bridges
Comanche County, OK · avg 1976 · 593 bridges
Prince George's County, MD · avg 1976 · 576 bridges
New Castle County, DE · avg 1976 · 527 bridges

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

All 290 Good 116 Fair 160 Poor 14

All bridges (290)

Sort:

Knox County Bridge Snapshot

Condition distribution

Knox County's Poor-condition bridges carry 1,712 vehicle crossings a day

45.5% of Knox County's bridges have passed the 50-year mark

One structure carries 43.8% of the county's Poor-condition bridge traffic

How Knox 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

All bridges (290)

JONES ROAD

BOWMAN ROAD

MAIN STREET ROAD

ROBINSON ROAD

VASH ROAD

SUMMERS ROAD

SCEPTER ROAD

FORT KNOX DRIVE

MCCORMICK ROAD

HUNLEY ROAD

P. PERRY ROAD

CAMP ARTHUR ROAD

OLD US 41

WASHINGTON STREET

6TH STREET

ST CLAIRE ROAD

OLD DECKER ROAD

US 50 EB

US 50 WB

US 50 EBL

SR 67

US 41 SB

US 50 WBL

MAIN STREET ROAD

US 41 SB

BICKNELL ROAD

SR 67 & US 41 RAMP

COON HUNTER ROAD

US 50 WB

SR 550

US 41 NB (MIDDLE)

US 50 EB

US 41 SB

US 50 EB

US 50 WB

2ND STREET

SR 58

US 41 NB

BROUILETTE ROAD

SR 67

SR 159

SR 550

US 41 SB

SR 58

SR 358

TR 257

LONG ROAD

GRANDVIEW ROAD

SPRINGTOWN ROAD

SR 550

Related