Total bridges
109
Public highway bridges in Johnson County
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.
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.
When Johnson County's bridges were built
109 bridges with a recorded construction year, grouped by decade
- 1910s 1
1910–1919
1 bridges
- 1920s 1
1920–1929
1 bridges
- 1930s 9
1930–1939
9 bridges
- 1940s 7
1940–1949
7 bridges
- 1950s
1950–1959
26 bridges
- 1960s 7
1960–1969
7 bridges
- 1970s
1970–1979
19 bridges
- 1980s 9
1980–1989
9 bridges
- 1990s
1990–1999
14 bridges
- 2000s 7
2000–2009
7 bridges
- 2010s 8
2010–2019
8 bridges
- 2020s 1
2020–2029
1 bridges
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.
| 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.
Poor-condition bridges (5)
NFA A375
PoorOver: ROAN CREEK
SE OFF SR167-SW OF AIRPRT, Johnson, TN
Built 1962 Load: 11.0 t ADT: 100
FAS 167
PoorOver: DOE CREEK
IN DOEVILLE, Johnson, TN
Built 1945 Load: 15.2 t ADT: 1,413
NFA A409 (SA 4624)
PoorOver: ROAN CREEK
LT DRY RUN RD-S OFF SR167, Johnson, TN
Built 1975 Load: 17.5 t ADT: 160
NFA A302
PoorOver: FORGE CREEK
S OF SR167 E OF MTN CITY, Johnson, TN
Built 1978 Load: 24.3 t ADT: 70
NFA A064
PoorOver: DOE CREEK
S OF SR67-N OF SR167, Johnson, TN
Built 1975 Load: 25.2 t ADT: 40
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.