County profile · official public datasets

Nassau County, NY

328 public highway bridges tracked in the FHWA National Bridge Inventory: 28.4% rated Good, 70.4% Fair, 1.2% Poor.

Compiled by PlainBridges

328
Public bridges: 28.4%
Good condition: 1.2%
Poor condition

The verdict

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

Nassau County pairs a top-5% lowest Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 2%
lowest Poor share in state: 1.2%
Poor-condition share: 328
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.

Nassau County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Nassau County ranks #1 of 62 New York counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 1.2%). Nassau County, New York contains 328 public highway bridges. Roughly 28.4% are rated “Good,” 70.4% “Fair,” and 1.2% “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.

Total bridges

328

Public highway bridges in Nassau County

Good condition

28.4%

93 of 328 rated 7-9

Fair condition

70.4%

231 of 328 rated 5-6

Poor condition

1.2%

4 of 328 rated 4 or below

In-state Poor-share rank

#1 of 62

Among New York counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 328 NBI-tracked bridges by lowest applicable component rating.

Good

28.4% (93)

Fair

70.4% (231)

Poor

1.2% (4)

Nassau County's Poor-condition bridges carry 133,968 vehicle crossings a day

That is 1.1% of the county's reported daily bridge traffic on 1% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 44,656 crossings a day against 29,336 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 298 of 328 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

80.5% of Nassau County's bridges have passed the 50-year mark

264 of the 328 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 28.4% 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 96.4% of the county's Poor-condition bridge traffic

RTE 908G over RTE I495, built 1968, carries 129,086 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 4-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 133,968 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

1
1900s

3
1910s

2
1920s

11
1930s

76
1940s

19
1950s

75
1960s

68
1970s

12
1980s

6
1990s

30
2000s

16
2010s

8
2020s

1

What this shows Construction peaked in the 1930s, when 76 of the county's bridges still in the inventory were built, which is 23.2% of those with a recorded year. That cohort is now 85 to 94 years old in the 2024 inventory. Its average build year is 1959, 13 years older than the New York average of 1972.

How Nassau County compares with New York's closest counties by inventory size

The 5 New York counties nearest Nassau County in number of bridges, with their condition splits. Its 1.2% Poor share is the 1st-lowest of these 6. Its average build year of 1959 against a peer-group mean of 1967 is 8 years older.

Showing the 5 closest of 61 New York counties eligible for comparison.

Bridge inventory size and condition shares for Nassau County and the 5 New York counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Albany County	343	29.7%	65%	5.2%	1975
Dutchess County	332	22.6%	60.8%	16.6%	1967
Nassau County (this page)	328	28.4%	70.4%	1.2%	1959
Jefferson County	316	41.5%	47.8%	10.8%	1971
St. Lawrence County	312	59.9%	33.3%	6.7%	1976
Bronx County	311	16.1%	75.6%	8.4%	1945

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 Nassau 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 Nassau County, both outside New York so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NY (328 bridges here).

Henry County, IL · 328 bridges
Jones County, MS · 329 bridges
Knox County, NE · 329 bridges
Mercer County, OH · 329 bridges

Similar average build year

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

Tulare County, CA · avg 1959 · 589 bridges
Barton County, KS · avg 1959 · 449 bridges
Marion County, KS · avg 1959 · 324 bridges
Hampshire County, MA · avg 1959 · 259 bridges

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

All 328 Good 93 Fair 231 Poor 4

Fair-condition bridges (231)

Sort:

Nassau County Bridge Snapshot

Condition distribution

Nassau County's Poor-condition bridges carry 133,968 vehicle crossings a day

80.5% of Nassau County's bridges have passed the 50-year mark

One structure carries 96.4% of the county's Poor-condition bridge traffic

How Nassau County compares with New York'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 (231)

RTE I495

CARLE ROAD

RTE 24

RTE I495

RTE 135

GLEN COVE ROAD

RTE 135

RTE I495

RTE I495

RTE 908G

OLD COUNTRY ROAD

RTE 24

RTE 106

POWELL AVENUE

RTE 135

MERRICK ROAD

Charles Lindbergh

RTE 135

SOUTHERN PARKWAY

CENTRAL AVENUE

RTE 25

RTE 27

BRANCH BOULEVARD

HICKS ROAD

POWELLS LANE

FULTON STREET

RTE 25B

ELLISON AVENUE

SOUTHLAND DRIVE

SANDS POINT PARK

DALY BOULEVARD

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