County profile · official public datasets

Somerset County, NJ

397 public highway bridges tracked in the FHWA National Bridge Inventory: 33% rated Good, 57.4% Fair, 9.6% Poor.

397
Public bridges
33%
Good condition
9.6%
Poor condition

The verdict

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

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

19th
of 21 on Poor share
9.6%
Poor-condition share
397
public highway bridges
1970
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.

Somerset County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Somerset County ranks #19 of 21 New Jersey counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.6%). Somerset County, New Jersey contains 397 public highway bridges. Roughly 33% are rated “Good,” 57.4% “Fair,” and 9.6% “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.

Total bridges

397

Public highway bridges in Somerset County

Good condition

33%

131 of 397 rated 7-9

Fair condition

57.4%

228 of 397 rated 5-6

Poor condition

9.6%

38 of 397 rated 4 or below

In-state Poor-share rank

#19 of 21

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

Condition distribution

Share of 397 NBI-tracked bridges by lowest applicable component rating.

Good
33% (131)
Fair
57.4% (228)
Poor
9.6% (38)

Somerset County's Poor-condition bridges carry 639,320 vehicle crossings a day

That is 10% of the county's reported daily bridge traffic on 9.6% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 16,824 crossings a day against 9,020 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 397 of 397 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

54.2% of Somerset County's bridges have passed the 50-year mark

215 of the 397 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 33% 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 9.2% of the county's Poor-condition bridge traffic

I-78 EASTBOUND over I-78 RAMP "A", built 1963, carries 58,865 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 38-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 639,320 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Somerset County's bridges were built

397 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 108 of the county's bridges still in the inventory were built, which is 27.2% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1970) matches the New Jersey average (1966).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 New Jersey counties nearest Somerset County in number of bridges, with their condition splits. Its 9.6% Poor share is the 5th-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1965 is 5 years newer.

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

Bridge inventory size and condition shares for Somerset County and the 5 New Jersey counties closest to it in inventory size
County Bridges Poor
Mercer County 414 9.2%
Union County 409 4.2%
Somerset County (this page) 397 9.6%
Hunterdon County 373 7.5%
Burlington County 356 10.1%
Passaic County 333 3.3%

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

Similar inventory size

Nearest county inventories outside NJ (397 bridges here).

Similar average build year

Nearest mean year-built outside NJ (1970 here).

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

All 397 Good 131 Fair 228 Poor 38

All bridges (397)

WOODLAWN AVE

Fair

Over: I-287

.1MI SOUTH OF RT 202&206, Somerset, NJ

Built 1963 Load: 36.3 t ADT: 5,240

BURNT HILL ROAD

Fair

Over: ROCK BROOK

0.4 MI N. OF CR 518, Somerset, NJ

Built 1998 Load: 36.3 t ADT: 1,190

MOUNTAIN AVE

Fair

Over: PETERS BROOK

.24 MI SO. OF US 22, Somerset, NJ

Built 1901 Load: 36.3 t ADT: 5,455

CHIMNEY ROCK RD

Fair

Over: CUCKELS BROOK

0.04 MI N OF EAST MAIN ST, Somerset, NJ

Built 1971 Load: 36.3 t ADT: 5,395

MADISONVILLE RD

Fair

Over: PASSAIC RIVER

.46 MI E of N Maple Ave, Somerset, NJ

Built 1975 Load: 36.3 t ADT: 7,325

GROVE ST.

Fair

Over: US 22 EB

.84 MI EAST OF US 202&206, Somerset, NJ

Built 1953 Load: 37.2 t ADT: 6,121

US 22

Fair

Over: MIDDLE BROOK

0.62 MI E OF JCT I-287, Somerset, NJ

Built 1929 Load: 37.2 t ADT: 63,615

Dutch-Harlin-CR604

Fair

Over: TRENTON LINE (CSXT)

1.07 MI WEST OF US206 JCT, Somerset, NJ

Built 1926 Load: 37.2 t ADT: 1,300

HAMILTON ROAD

Fair

Over: ROYCE BROOK

.83 MI EAST OF RT 206, Somerset, NJ

Built 1978 Load: 37.2 t ADT: 2,617

CR 614

Fair

Over: N BR RARITAN RIVER

1.46 mi E of US 22, Somerset, NJ

Built 2005 Load: 38.1 t ADT: 8,021

COUNTRY CLUB RD

Fair

Over: TRIB TO PETERS BROOK

0.22 mi N of NJ 28, Somerset, NJ

Built 1975 Load: 38.1 t ADT: 7,148

US 202

Fair

Over: US 206 SB & NJ 28

0.7 MI S. OF US JCT 22, Somerset, NJ

Built 1994 Load: 39.0 t ADT: 100,054

Route I-287

Fair

Over: CANAL RD D&R RARITAN&RR

1.2MI SOUTH OF RT 28, Somerset, NJ

Built 1960 Load: 39.0 t ADT: 159,760

WASHINGTON AVE

Fair

Over: I-287

1.93 MI NORTH OF EXIT 26, Somerset, NJ

Built 1966 Load: 39.0 t ADT: 2,309

I-287 N.B.

Fair

Over: PASSAIC RIVER

I-287 & PASSAIC RIVER, Somerset, NJ

Built 1968 Load: 39.0 t ADT: 27,510

DEAD RIVER ROAD

Fair

Over: ROUTE I-78

1.24 MI W OF I-78 EXIT 36, Somerset, NJ

Built 1965 Load: 39.0 t ADT: 1,230

COUNTRY CLUB ROAD

Fair

Over: CHAMBERS BROOK

0.05M N OF CEDAR BROOK RD, Somerset, NJ

Built 1977 Load: 39.0 t ADT: 5,736

LAKE ROAD

Fair

Over: HARRISONS BROOK

0.69 mi East of RT 525, Somerset, NJ

Built 1969 Load: 39.0 t ADT: 3,293

SYCAMORE AVENUE

Fair

Over: GREEN BROOK

0.1 MI W. OF NJ ROUTE 28, Somerset, NJ

Built 1910 Load: 39.0 t ADT: 568

US 202/206

Fair

Over: CHAMBERS BROOK

0.13 Miles S of I-78 Jct., Somerset, NJ

Built 1989 Load: 39.9 t ADT: 23,668

I-78 WB RAMP A

Fair

Over: I-287 SB AND RAMP

.2 MI SOUTH OF I-287 JCT, Somerset, NJ

Built 1963 Load: 39.9 t ADT: 22,401

MORGAN LANE

Fair

Over: CUCKELS BROOK

0.07 MI NO OF RT 28, Somerset, NJ

Built 1980 Load: 39.9 t ADT: 1,840

DAVIDSON AVE

Fair

Over: D&R CANAL TRIBUTARY

0.23 mi N OF NEW BRUNS.Rd, Somerset, NJ

Built 1980 Load: 39.9 t ADT: 12,685

MAIN STREET(CR527)

Fair

Over: RARITAN RIVER

0.73 mi S of NJ 28, Somerset, NJ

Built 1875 Load: 39.9 t ADT: 13,656

CR 518

Fair

Over: Trib to Bedens Brook

1.47 mi. west of US 206, Somerset, NJ

Built 2007 Load: 40.8 t ADT: 9,046

I 287 SB

Fair

Over: N. FINLEY AVE (CR 613)

1.35 MI S of Intchg 30, Somerset, NJ

Built 1966 Load: 41.7 t ADT: 48,607

CR 523

Fair

Over: LAMINGTON RIVER

1.15 mi N of CR 517, Somerset, NJ

Built 1977 Load: 41.7 t ADT: 5,588

HARLINGEN ROAD

Fair

Over: PIKE RUN

.35 MI W. OF MILL POND RD, Somerset, NJ

Built 1921 Load: 41.7 t ADT: 700

BURNT MILLS RD

Fair

Over: I-78 AND RAMPS A & B

0.48mi W. of I-287, Somerset, NJ

Built 1965 Load: 42.1 t ADT: 14

I-287 N.B.

Fair

Over: MOUNT AIRY ROAD (CO.525)

AT I-287 EXIT 26, Somerset, NJ

Built 1968 Load: 42.6 t ADT: 56,404

US 22 EB

Fair

Over: STATION ROAD (CR.679)

1 MI WEST OF RT 28 JCT, Somerset, NJ

Built 1942 Load: 43.4 t ADT: 24,248

RTE US 22 WB

Fair

Over: STATION ROAD (CO.679)

1MI WEST OF RT 28 JCT, Somerset, NJ

Built 1941 Load: 43.4 t ADT: 17,080

NJ 28

Fair

Over: I-287

INTERSECTION with I-287, Somerset, NJ

Built 1960 Load: 43.5 t ADT: 20,812

US 206

Fair

Over: PIKE RUN

2 MI SOUTH OF RT 514 JCT, Somerset, NJ

Built 1927 Load: 43.5 t ADT: 25,785

COUNTY ROUTE 665

Fair

Over: LAMINGTON RIVER

1.18 mi N CR 614, Somerset, NJ

Built 1988 Load: 43.5 t ADT: 10,424

PIERCE STREET

Fair

Over: TRIB. OF RARITAN RIVER

0.2 MI W. OF DAVIDSON AVE, Somerset, NJ

Built 2001 Load: 43.5 t ADT: 2,361

FOOTHILL ROAD

Fair

Over: US 22 AND I-287 RAMP

0.39 MI W OF JCT I-287, Somerset, NJ

Built 1960 Load: 44.5 t ADT: 6,038

US 202 AND 206

Fair

Over: I-287

0.85 MI NORTH OF RT 22, Somerset, NJ

Built 1963 Load: 44.5 t ADT: 75,814

STIRLING ROAD

Fair

Over: I-78

2.36 MI E OF 287 EXIT 36, Somerset, NJ

Built 1970 Load: 44.5 t ADT: 9,840

I-287 SB

Fair

Over: MT AIRY RD(CR 525)

4.4MI NORTH OF 202&206, Somerset, NJ

Built 1968 Load: 45.4 t ADT: 56,404

CHIMNEY ROCK RD

Fair

Over: MIDDLE BROOK

0.74 mi N of US 22, Somerset, NJ

Built 1920 Load: 45.4 t ADT: 11,646

CR 525 NB

Fair

Over: I-78

I-78 EXIT 33, Somerset, NJ

Built 1995 Load: 46.3 t ADT: 13,270

WILLIAM STREET

Fair

Over: ROSS BROOK

0.1 MI EAST OF GROVE ST., Somerset, NJ

Built 1928 Load: 46.3 t ADT: 3,908

Ramp H

Fair

Over: I-287 NB and Ramp H

I-78 & I-287 Interchange, Somerset, NJ

Built 2020 Load: 46.7 t ADT: 21,878

THOMPSON AV(CO525)

Fair

Over: US 22

0.8 MI EAST OF I-287 JCT, Somerset, NJ

Built 1953 Load: 47.2 t ADT: 6,525

WATCHUNG AVE

Fair

Over: U.S. 22

8.93 MI SOUTH OF I-287, Somerset, NJ

Built 1956 Load: 47.2 t ADT: 12,289

I-287

Fair

Over: NJT (Raritan Valley)

0.7 MI SOUTH OF NJ 28 JCT, Somerset, NJ

Built 1960 Load: 47.2 t ADT: 148,249

PRINCETON AVENUE

Fair

Over: VAN HORN BROOK

0.5 MILES E. OF US 206, Somerset, NJ

Built 1978 Load: 47.2 t ADT: 3,787

TOP OF WORLD WAY

Fair

Over: E BRANCH OF MIDDLE BROOK

.05 MI SO.OF WASH VALL RD, Somerset, NJ

Built 1996 Load: 47.2 t ADT: 192

DAVIDSON AVE.

Fair

Over: I-287

0.26 MI N OF CR 527, Somerset, NJ

Built 1960 Load: 48.1 t ADT: 8,727

Read our methodology - how this data is sourced, computed, and verified.

Related

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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.