County profile · official public datasets

Carbon County, PA

134 public highway bridges tracked in the FHWA National Bridge Inventory: 20.9% rated Good, 60.4% Fair, 18.7% Poor.

134
Public bridges: 20.9%
Good condition: 18.7%
Poor condition

The verdict

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

Carbon County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

59th
of 67 on Poor share: 18.7%
Poor-condition share: 134
public highway bridges: 1960
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.

Carbon County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Carbon County ranks #59 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 18.7%). Carbon County, Pennsylvania contains 134 public highway bridges. Roughly 20.9% are rated “Good,” 60.4% “Fair,” and 18.7% “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

134

Public highway bridges in Carbon County

Good condition

20.9%

28 of 134 rated 7-9

Fair condition

60.4%

81 of 134 rated 5-6

Poor condition

18.7%

25 of 134 rated 4 or below

In-state Poor-share rank

#59 of 67

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

Condition distribution

Share of 134 NBI-tracked bridges by lowest applicable component rating.

Good

20.9% (28)

Fair

60.4% (81)

Poor

18.7% (25)

Carbon County's Poor-condition bridges carry 76,950 vehicle crossings a day

That is 8.1% of the county's reported daily bridge traffic on 18% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,206 crossings a day against 10,336 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 133 of 134 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

75.4% of Carbon County's bridges have passed the 50-year mark

101 of the 134 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 20.9% 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 29% of the county's Poor-condition bridge traffic

PA TPK (I-476) over MUD RUN, built 1957, carries 22,283 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 76,950 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

3
1900s

1
1910s

8
1920s

8
1930s

16
1940s

4
1950s

27
1960s

29
1970s

6
1980s

5
1990s

5
2000s

5
2010s

16
2020s

1

What this shows Construction peaked in the 1960s, when 29 of the county's bridges still in the inventory were built, which is 21.6% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1960, 10 years older than the Pennsylvania average of 1970.

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

The 5 Pennsylvania counties nearest Carbon County in number of bridges, with their condition splits. Its 18.7% Poor share is the 4th-lowest of these 6. Its average build year of 1960 against a peer-group mean of 1970 is 10 years older.

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

Bridge inventory size and condition shares for Carbon County and the 5 Pennsylvania counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Fulton County	159	32.1%	56%	11.9%	1967
Pike County	158	35.4%	38.6%	25.9%	1971
Wyoming County	140	42.1%	35%	22.9%	1973
Carbon County (this page)	134	20.9%	60.4%	18.7%	1960
Elk County	127	39.4%	49.6%	11%	1973
Sullivan County	119	43.7%	47.1%	9.2%	1967

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 Carbon 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 Carbon County, both outside Pennsylvania so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside PA (134 bridges here).

Anchorage County, AK · 134 bridges
Knott County, KY · 134 bridges
Murray County, MN · 134 bridges
Steele County, MN · 134 bridges

Similar average build year

Nearest mean year-built outside PA (1960 here).

Windham County, VT · avg 1960 · 337 bridges
Plymouth County, MA · avg 1960 · 287 bridges
Cheshire County, NH · avg 1960 · 192 bridges
Washington County, NY · avg 1960 · 189 bridges

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

All 134 Good 28 Fair 81 Poor 25

All bridges (134)

Sort:

Carbon County Bridge Snapshot

Condition distribution

Carbon County's Poor-condition bridges carry 76,950 vehicle crossings a day

75.4% of Carbon County's bridges have passed the 50-year mark

One structure carries 29% of the county's Poor-condition bridge traffic

How Carbon 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

All bridges (134)

T-459 GRIST MILL

PA TPK (I-476)

SR 2004 (LR 13014)

PA TPK (I-476)

PA TPK (I-476)

PA TPK (I-476)

TONOLLI ENTR RD

PA TPK (I-476)

Pohopoco Drive

SR0895 LR13001

SR 1001

PA 248 (LR163)

PA 895

PA TPK (I-476)

PA TPK (I-476)

SCENIC DRIVE

INDUSTRIAL PARK RD

T-444

SCENIC DRIVE

PA 534(LR 13018)

PA TPK (I-476)

PA 248 (LR 163)

SR 4010(APPL 1012)

INDUSTRIAL ROAD

I-80 (LR 1009)

PA TPK (I-476)

PA 93 (LR 170)

PA 93 (LR 170)

I-80 RAMPS H-G

SR 2019(LR 163 RP)

GLEN ONOKO BRIDGE

PA TPK (I-476)

PA940 (LR 408)

PA TPK (I-476)

PA TPK (I-476)

PA TPK RAMP AB

PA TPK (I-476 NB)

PA TPK (I-476 SB)

LORDVILLE ROAD

PA TPK (I-476 SB)

PA TPK (I-476 NB)

Quakake Rd SR4010

SR 2007(LR 13047)

SR 2008

KOCH RD

SR 903 (LR13046)

SR 1001 (LR 13012)

HENNING RD

N. MECKESVILLE RD

PA 902

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