County profile · official public datasets

Somerset County, PA

454 public highway bridges tracked in the FHWA National Bridge Inventory: 33% rated Good, 52.6% Fair, 14.3% Poor.

454
Public bridges: 33%
Good condition: 14.3%
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.

47th
of 67 on Poor share: 14.3%
Poor-condition share: 454
public highway bridges: 1969
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 #47 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 14.3%). Somerset County, Pennsylvania contains 454 public highway bridges. Roughly 33% are rated “Good,” 52.6% “Fair,” and 14.3% “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

454

Public highway bridges in Somerset County

Good condition

33%

150 of 454 rated 7-9

Fair condition

52.6%

239 of 454 rated 5-6

Poor condition

14.3%

65 of 454 rated 4 or below

In-state Poor-share rank

#47 of 67

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

Condition distribution

Share of 454 NBI-tracked bridges by lowest applicable component rating.

Good

33% (150)

Fair

52.6% (239)

Poor

14.3% (65)

Somerset County's Poor-condition bridges carry 28,299 vehicle crossings a day

That is 2.3% of the county's reported daily bridge traffic on 14.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 442 crossings a day against 2,704 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 453 of 454 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

56.6% of Somerset County's bridges have passed the 50-year mark

257 of the 454 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 22.4% of the county's Poor-condition bridge traffic

US 219 SBL over T685 MILLER ROAD, built 1969, carries 6,344 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 65-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 28,299 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

7
1900s

19
1910s

24
1920s

21
1930s

59
1940s

19
1950s

28
1960s

59
1970s

24
1980s

21
1990s

42
2000s

42
2010s

80
2020s

9

What this shows Construction peaked in the 2010s, when 80 of the county's bridges still in the inventory were built, which is 17.6% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year (1969) matches the Pennsylvania average (1970).

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

The 5 Pennsylvania counties nearest Somerset County in number of bridges, with their condition splits. Its 14.3% Poor share is the 4th-lowest of these 6. Its average build year of 1969 against a peer-group mean of 1974 is 5 years older.

Showing the 5 closest of 66 Pennsylvania counties eligible for comparison.

Bridge inventory size and condition shares for Somerset County and the 5 Pennsylvania counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Luzerne County	457	28.9%	45.5%	25.6%	1972
Somerset County (this page)	454	33%	52.6%	14.3%	1969
Dauphin County	449	22%	69.5%	8.5%	1972
Erie County	442	37.8%	52.7%	9.5%	1976
Mercer County	438	39.3%	45.2%	15.5%	1972
Tioga County	429	49.4%	47.3%	3.3%	1977

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 Pennsylvania so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside PA (454 bridges here).

Hamilton County, IN · 454 bridges
Forsyth County, NC · 454 bridges
Woodbury County, IA · 455 bridges
Hunt County, TX · 456 bridges

Similar average build year

Nearest mean year-built outside PA (1969 here).

Cook County, IL · avg 1969 · 1,721 bridges
Fresno County, CA · avg 1969 · 916 bridges
Cuyahoga County, OH · avg 1969 · 871 bridges
Ventura County, CA · avg 1969 · 501 bridges

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

All 454 Good 150 Fair 239 Poor 65

Good-condition bridges (150)

Sort:

Somerset County Bridge Snapshot

Condition distribution

Somerset County's Poor-condition bridges carry 28,299 vehicle crossings a day

56.6% of Somerset County's bridges have passed the 50-year mark

One structure carries 22.4% of the county's Poor-condition bridge traffic

How Somerset County compares with Pennsylvania'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 (150)

US 30

SR 3023

US 219 NBL

SR 1002

T-353 MOSER ROAD

SR 4009 Husband Rd

SR 1003

PA 403

SR 4015

T-858 Mt. Zion Rd

US 219

SR 4023

US 219

SR 3025

US 219

US 219

PA 601

T-816 Crumb Road

SR 4027

PA 160

SR 3019

Lambertsville Rd

PA 31

T580 SHAFFER RUN R

T580 SHAFFER RUN R

PA 601

SR 1015

PA 985

PA 160

SR 3001

SR 4005

US 219

SR 3014

SR 4005 (LR 55064)

SR 2037

SR 2006

PA 669

SR 3033

SR 3010

SR 4016

SR 1003

SR 4008

PA 601

SR 2025

PA 281

SR 2018

SR 2037

PA 281

SR 4021

SOUTH WOLF ROCK RD

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