County profile · official public datasets

Kauai County, HI

90 public highway bridges tracked in the FHWA National Bridge Inventory: 36.7% rated Good, 52.2% Fair, 11.1% Poor.

90
Public bridges: 36.7%
Good condition: 11.1%
Poor condition

The verdict

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

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

4th
of 4 on Poor share: 11.1%
Poor-condition share: 90
public highway bridges: 1959
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.

Kauai County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Kauai County ranks #4 of 4 Hawaii counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 11.1%). Kauai County, Hawaii contains 90 public highway bridges. Roughly 36.7% are rated “Good,” 52.2% “Fair,” and 11.1% “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

Public highway bridges in Kauai County

Good condition

36.7%

33 of 90 rated 7-9

Fair condition

52.2%

47 of 90 rated 5-6

Poor condition

11.1%

10 of 90 rated 4 or below

In-state Poor-share rank

#4 of 4

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

Condition distribution

Share of 90 NBI-tracked bridges by lowest applicable component rating.

Good

36.7% (33)

Fair

52.2% (47)

Poor

11.1% (10)

Kauai County's Poor-condition bridges carry 96,773 vehicle crossings a day

That is 11% of the county's reported daily bridge traffic on 11.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 9,677 crossings a day against 10,203 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 90 of 90 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

71.1% of Kauai County's bridges have passed the 50-year mark

64 of the 90 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 36.7% 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 32.7% of the county's Poor-condition bridge traffic

KUHIO HWY over WAILUA RIVER, built 1945, carries 31,600 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 10-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 96,773 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

4
1910s

8
1920s

7
1930s

16
1940s

8
1950s

7
1960s

12
1970s

3
1980s

5
1990s

3
2000s

5
2010s

7
2020s

5

What this shows Construction peaked in the 1930s, when 16 of the county's bridges still in the inventory were built, which is 17.8% of those with a recorded year. That cohort is now 85 to 94 years old in the 2024 inventory. Its average build year (1959) matches the Hawaii average (1961).

How Kauai County compares with Hawaii's closest counties by inventory size

The 3 Hawaii counties nearest Kauai County in number of bridges, with their condition splits. Its 11.1% Poor share is the 4th-lowest of these 4. Its average build year of 1959 against a peer-group mean of 1959 is in line with the group.

Bridge inventory size and condition shares for Kauai County and the 3 Hawaii counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Honolulu County	682	35.8%	57.3%	6.9%	1963
Hawaii County	237	44.7%	51.1%	4.2%	1956
Maui County	185	33.5%	60.5%	5.9%	1958
Kauai County (this page)	90	36.7%	52.2%	11.1%	1959

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

Similar inventory size

Nearest county inventories outside HI (90 bridges here).

Greenlee County, AZ · 90 bridges
Clay County, FL · 90 bridges
Taylor County, FL · 90 bridges
Monroe County, GA · 90 bridges

Similar average build year

Nearest mean year-built outside HI (1959 here).

Tulare County, CA · avg 1959 · 589 bridges
Barton County, KS · avg 1959 · 449 bridges
Nassau County, NY · avg 1959 · 328 bridges
Marion County, KS · avg 1959 · 324 bridges

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

All 90 Good 33 Fair 47 Poor 10

Good-condition bridges (33)

Sort:

Kauai County Bridge Snapshot

Condition distribution

Kauai County's Poor-condition bridges carry 96,773 vehicle crossings a day

71.1% of Kauai County's bridges have passed the 50-year mark

One structure carries 32.7% of the county's Poor-condition bridge traffic

How Kauai County compares with Hawaii's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Good-condition bridges (33)

Kamalu Rd

KAMALU RD.

Anini Road

KAUMUALII HWY

MALUHIA RD

HOOMANA RD

KAUMUALII HWY

KAUMUALII HWY

KAUMUALII HWY

Kekaha Rd

KAHUNA RD.

KAUMUALII HWY

KAUMUALII HWY

KUHIO HWY

IMILOA RD

KAUMUALII HWY

KAPAIA ROAD

Kuhio Hwy

KUHIO HWY

KUHIO HWY

Kaumualii Highway

KUHIO HWY

Kuhio Hwy

KAUMUALII HWY

KUHIO HWY

HALEWILI RD

PUUOPAE ROAD

Kaumualii Highway

KAUMUALII HWY

HOONANI RD

Kuhio Hwy

KAWAIHAU RD

Opaekaa Road

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