County profile · official public datasets

Union County, NJ

409 public highway bridges tracked in the FHWA National Bridge Inventory: 17.8% rated Good, 78% Fair, 4.2% Poor.

409
Public bridges: 17.8%
Good condition: 4.2%
Poor condition

The verdict

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

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

Top 29%
lowest Poor share in state: 4.2%
Poor-condition share: 409
public highway bridges: 1967
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.

Union County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Union County ranks #6 of 21 New Jersey counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.2%). Union County, New Jersey contains 409 public highway bridges. Roughly 17.8% are rated “Good,” 78% “Fair,” and 4.2% “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

409

Public highway bridges in Union County

Good condition

17.8%

73 of 409 rated 7-9

Fair condition

78%

319 of 409 rated 5-6

Poor condition

4.2%

17 of 409 rated 4 or below

In-state Poor-share rank

#6 of 21

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

Condition distribution

Share of 409 NBI-tracked bridges by lowest applicable component rating.

Good

17.8% (73)

Fair

78% (319)

Poor

4.2% (17)

Union County's Poor-condition bridges carry 352,273 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 4.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 20,722 crossings a day against 30,191 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 408 of 409 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

66.5% of Union County's bridges have passed the 50-year mark

272 of the 409 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 17.8% 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 20.9% of the county's Poor-condition bridge traffic

US 22 over ECHO LAKE, built 1929, carries 73,690 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 17-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 352,273 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

2
1900s

8
1910s

9
1920s

22
1930s

17
1940s

19
1950s

67
1960s

72
1970s

83
1980s

43
1990s

17
2000s

20
2010s

24
2020s

6

What this shows Construction peaked in the 1970s, when 83 of the county's bridges still in the inventory were built, which is 20.3% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1967) matches the New Jersey average (1966).

How Union County compares with New Jersey's closest counties by inventory size

The 5 New Jersey counties nearest Union County in number of bridges, with their condition splits. Its 4.2% Poor share is the 2nd-lowest of these 6. Its average build year of 1967 against a peer-group mean of 1965 is in line with the group.

Showing the 5 closest of 20 New Jersey counties eligible for comparison.

Bridge inventory size and condition shares for Union County and the 5 New Jersey counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Mercer County	414	40.3%	50.5%	9.2%	1975
Union County (this page)	409	17.8%	78%	4.2%	1967
Somerset County	397	33%	57.4%	9.6%	1970
Hunterdon County	373	20.1%	72.4%	7.5%	1949
Burlington County	356	26.4%	63.5%	10.1%	1969
Passaic County	333	22.2%	74.5%	3.3%	1963

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

Similar inventory size

Nearest county inventories outside NJ (409 bridges here).

Benton County, AR · 410 bridges
Pottawatomie County, OK · 408 bridges
Jefferson County, MO · 411 bridges
Pittsburg County, OK · 411 bridges

Similar average build year

Nearest mean year-built outside NJ (1967 here).

Los Angeles County, CA · avg 1967 · 3,547 bridges
Allegheny County, PA · avg 1967 · 1,294 bridges
Sonoma County, CA · avg 1967 · 609 bridges
Merced County, CA · avg 1967 · 528 bridges

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

All 409 Good 73 Fair 319 Poor 17

All bridges (409)

Sort:

Union County Bridge Snapshot

Condition distribution

Union County's Poor-condition bridges carry 352,273 vehicle crossings a day

66.5% of Union County's bridges have passed the 50-year mark

One structure carries 20.9% of the county's Poor-condition bridge traffic

How Union County compares with New Jersey'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 (409)

PROSPECT AVENUE

GARDEN ST PARKWAY

GSP RAMP NW-D

RELOC.BAYWAY AVE.

NJTPK SNO ROADWAY

RARITAN ROAD

GSP

NJTPK SNI ROADWAY

INT 13 RAMP SOT

NJTPK SNO/RAMP SOT

ELIZABETH AVENUE

LINDEN AVENUE

RANDOLPH ROAD

WARINANCO PARK DR

UNION AVENUE

NJ 35

NJTPK INT 13A SIT

NJTPK 103 U-TURN

RAMP F

NJ TPK INT.13 SIT

ROUTE NJ 124

NJ 27

WEST LINDEN AVENUE

I-78

Cooper Road

MLLTWN RD (CR 636)

Sprngfld Av CR 577

N.BROAD ST (CR623)

TPK NSI ROADWAY

NJTPK NSI&SNI RWY

US 22 WB

I-78

I-78

WATCHUNG AVENUE

LAWRENCE AV(CR514)

PLAINFIELD AVENUE

MSL AV-CR 509 SPUR

MARTINE AVE CR655

NJ TPK INT.13A TN

NJ TPK RWYS

NJTPK NSI&SNI RWYS

RAMP TNI

VAUX HALL RD CR630

WOOD AVE. (CR 617)

78 WB INNER&RAMP O

NJTPK NSI-SNI RWYS

NJ TPK NSO RWY

RAMP GA

EXIT RAMP TO GSP

GSP NB & SB

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