County profile · official public datasets

Johnson County, TN

109 public highway bridges tracked in the FHWA National Bridge Inventory: 44% rated Good, 51.4% Fair, 4.6% Poor.

109
Public bridges: 44%
Good condition: 4.6%
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 an older average build year than the state inventory.

63rd
of 95 on Poor share: 4.6%
Poor-condition share: 109
public highway bridges: 1972
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 #63 of 95 Tennessee counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.6%). Johnson County, Tennessee contains 109 public highway bridges. Roughly 44% are rated “Good,” 51.4% “Fair,” and 4.6% “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

109

Public highway bridges in Johnson County

Good condition

44%

48 of 109 rated 7-9

Fair condition

51.4%

56 of 109 rated 5-6

Poor condition

4.6%

5 of 109 rated 4 or below

In-state Poor-share rank

#63 of 95

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

Condition distribution

Share of 109 NBI-tracked bridges by lowest applicable component rating.

Good

44% (48)

Fair

51.4% (56)

Poor

4.6% (5)

Johnson County's Poor-condition bridges carry 1,783 vehicle crossings a day

That is 1% of the county's reported daily bridge traffic on 4.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 357 crossings a day against 1,694 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 109 of 109 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

56% of Johnson County's bridges have passed the 50-year mark

61 of the 109 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 44% 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 79.2% of the county's Poor-condition bridge traffic

FAS 167 over DOE CREEK, built 1945, carries 1,413 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 5-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,783 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

1
1920s

1
1930s

9
1940s

7
1950s

26
1960s

7
1970s

19
1980s

9
1990s

14
2000s

7
2010s

8
2020s

1

What this shows Construction peaked in the 1950s, when 26 of the county's bridges still in the inventory were built, which is 23.9% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year is 1972, 5 years older than the Tennessee average of 1977.

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

The 5 Tennessee counties nearest Johnson County in number of bridges, with their condition splits. Its 4.6% Poor share is the 5th-lowest of these 6. Its average build year of 1972 against a peer-group mean of 1976 is in line with the group.

Showing the 5 closest of 94 Tennessee counties eligible for comparison.

Bridge inventory size and condition shares for Johnson County and the 5 Tennessee counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Houston County	118	45.8%	50.8%	3.4%	1978
Loudon County	117	53%	45.3%	1.7%	1971
Scott County	111	24.3%	71.2%	4.5%	1973
Johnson County (this page)	109	44%	51.4%	4.6%	1972
Decatur County	104	35.6%	63.5%	1%	1982
DeKalb County	100	23%	70%	7%	1977

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

Similar inventory size

Nearest county inventories outside TN (109 bridges here).

Mariposa County, CA · 109 bridges
Boone County, IL · 109 bridges
Gove County, KS · 109 bridges
Hodgeman County, KS · 109 bridges

Similar average build year

Nearest mean year-built outside TN (1972 here).

Santa Clara County, CA · avg 1972 · 964 bridges
Madison County, AL · avg 1972 · 710 bridges
Kern County, CA · avg 1972 · 668 bridges
York County, PA · avg 1972 · 569 bridges

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

All 109 Good 48 Fair 56 Poor 5

Fair-condition bridges (56)

Sort:

Johnson County Bridge Snapshot

Condition distribution

Johnson County's Poor-condition bridges carry 1,783 vehicle crossings a day

56% of Johnson County's bridges have passed the 50-year mark

One structure carries 79.2% of the county's Poor-condition bridge traffic

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

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (56)

NFA A063

NFA A128

NFA A024

NFA 2621 (SA 4621)

NFA 1076 (SA 4601)

NFA 2613 (SA 4605)

NFSR 298

FAP 34

NFA 1394 (SA 4603)

FAP 34

FAP 67

FAP 67

FAS 133

NFA 1076 (SA 4601)

NFA 2613 (SA 4605)

NFA A054

NFA A150

NFA A413

NFA A601

NFA 1394 (SA 4603)

NFA 2613 (SA 4605)

FAP 67

FAP 34

FAP 67

FAS 133

FAS 167

NFA A133

NFA A138

FAP 34

FAS 133

FAS 133

FAP 34

NFA 1394 (SA 4603)

NFA 2617 (SA 4617)

NFA A047

NFA A057

NFA A296

NFA A297 (SA 4625)

NFA A307

NFA A309 (SA 4608)

FAS 167

FAS 167

FAS 167

NFA 1394 (SA 4603)

FAP 34

FAP 34

FAP 34

FAP 34

FAS 91

FAS 91

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