County profile · official public datasets

Middlesex County, NJ

563 public highway bridges tracked in the FHWA National Bridge Inventory: 23.4% rated Good, 72.1% Fair, 4.4% Poor.

563
Public bridges: 23.4%
Good condition: 4.4%
Poor condition

The verdict

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

Middlesex County pairs a better-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

Top 33%
lowest Poor share in state: 4.4%
Poor-condition share: 563
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.

Middlesex County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Middlesex County ranks #7 of 21 New Jersey counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.4%). Middlesex County, New Jersey contains 563 public highway bridges. Roughly 23.4% are rated “Good,” 72.1% “Fair,” and 4.4% “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

563

Public highway bridges in Middlesex County

Good condition

23.4%

132 of 563 rated 7-9

Fair condition

72.1%

406 of 563 rated 5-6

Poor condition

4.4%

25 of 563 rated 4 or below

In-state Poor-share rank

#7 of 21

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

Condition distribution

Share of 563 NBI-tracked bridges by lowest applicable component rating.

Good

23.4% (132)

Fair

72.1% (406)

Poor

4.4% (25)

Middlesex County's Poor-condition bridges carry 402,662 vehicle crossings a day

That is 2.1% of the county's reported daily bridge traffic on 4.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 16,106 crossings a day against 29,014 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 563 of 563 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

58.6% of Middlesex County's bridges have passed the 50-year mark

330 of the 563 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 23.4% 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 16.8% of the county's Poor-condition bridge traffic

US 1 over FORRESTAL ROAD, built 1932, carries 67,565 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 25-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 402,662 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

4
1900s

3
1910s

6
1920s

21
1930s

26
1940s

28
1950s

67
1960s

65
1970s

125
1980s

44
1990s

92
2000s

48
2010s

34

What this shows Construction peaked in the 1970s, when 125 of the county's bridges still in the inventory were built, which is 22.2% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1972, 6 years newer than the New Jersey average of 1966.

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

The 5 New Jersey counties nearest Middlesex County in number of bridges, with their condition splits. Its 4.4% Poor share is the 2nd-lowest of these 6. Its average build year of 1972 against a peer-group mean of 1967 is 5 years newer.

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

Bridge inventory size and condition shares for Middlesex County and the 5 New Jersey counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Bergen County	577	19.1%	76.1%	4.9%	1964
Middlesex County (this page)	563	23.4%	72.1%	4.4%	1972
Morris County	508	19.7%	74.4%	5.9%	1964
Essex County	505	16.2%	81%	2.8%	1963
Monmouth County	505	32.9%	58.2%	8.9%	1971
Mercer County	414	40.3%	50.5%	9.2%	1975

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

Similar inventory size

Nearest county inventories outside NJ (563 bridges here).

Shawnee County, KS · 563 bridges
Summit County, OH · 563 bridges
Linn County, OR · 566 bridges
Larimer County, CO · 559 bridges

Similar average build year

Nearest mean year-built outside NJ (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 563 Good 132 Fair 406 Poor 25

All bridges (563)

Sort:

Middlesex County Bridge Snapshot

Condition distribution

Middlesex County's Poor-condition bridges carry 402,662 vehicle crossings a day

58.6% of Middlesex County's bridges have passed the 50-year mark

One structure carries 16.8% of the county's Poor-condition bridge traffic

How Middlesex 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 (563)

MENLO PARK DRIVE

US 9

PARKWAY N

RARITAN AVENUE

US1-US130 SB Conn.

WEST SECOND STREET

NJ 18

NSI & SNI Roadways

BRICK YARD RD.

RIVA AVENUE

NJ TPK SNO ROADWAY

NJTPK NSI RDWY

GARDEN ST PKWY SBI

FORSGATE RD EB

NJ ROUTE 18

DAVIDSON ROAD

GARDEN ST PKWY NBO

STATE ST. (CR611)

GSP SOUTHBOUND

GREEN BROOK ROAD

US 1

NJ 27 (Lake Av)

NJ 440 Ramp WK

SPOTSWD-GR.HILL RD

PERRINEVILLE ROAD

RTE NJ 18 SB RMP C

US 130 SB

GARDEN ST PKWY SB

HOFFMAN STATION RD

HGTSTN-CRAN STA RD

CRANBURY STATION R

NJ 440 Ramp VR

SCHOOL STREET

WOODBRIDGE AVE

FLRD GRV RD CR 655

SOUTH AVENUE

NJ 18 NB & RAMP A

CHURCH LANE

MOUNTAIN AVENUE

GEORGES ROAD

NJTPK INT.11 R.TNI

NJ TPK MP 92 U-TRN

ELMWOOD AVENUE

NJ 440 RAMP "J"

CRANBURY-HALF ACRE

Fresh Ponds Road

TEXAS ROAD

NJTPK NSO&RMP SASO

1ST AVENUE

NJ TPK NSO NSI RWY

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