County profile · official public datasets

Lehigh County, PA

381 public highway bridges tracked in the FHWA National Bridge Inventory: 29.4% rated Good, 59.3% Fair, 11.3% Poor.

381
Public bridges: 29.4%
Good condition: 11.3%
Poor condition

The verdict

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

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

Top 46%
lowest Poor share in state: 11.3%
Poor-condition share: 381
public highway bridges: 1966
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.

Lehigh County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Lehigh County ranks #31 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 11.3%). Lehigh County, Pennsylvania contains 381 public highway bridges. Roughly 29.4% are rated “Good,” 59.3% “Fair,” and 11.3% “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

381

Public highway bridges in Lehigh County

Good condition

29.4%

112 of 381 rated 7-9

Fair condition

59.3%

226 of 381 rated 5-6

Poor condition

11.3%

43 of 381 rated 4 or below

In-state Poor-share rank

#31 of 67

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

Condition distribution

Share of 381 NBI-tracked bridges by lowest applicable component rating.

Good

29.4% (112)

Fair

59.3% (226)

Poor

11.3% (43)

Lehigh County's Poor-condition bridges carry 224,278 vehicle crossings a day

That is 4% of the county's reported daily bridge traffic on 11.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 5,216 crossings a day against 15,019 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 381 of 381 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

61.4% of Lehigh County's bridges have passed the 50-year mark

234 of the 381 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 29.4% 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 34% of the county's Poor-condition bridge traffic

US 22(LR 771) over TWP.RD.567* MICKLEY ROAD, built 1952, carries 76,351 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 43-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 224,278 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

12
1910s

11
1920s

26
1930s

25
1940s

15
1950s

91
1960s

45
1970s

16
1980s

40
1990s

19
2000s

27
2010s

44
2020s

10

What this shows Construction peaked in the 1950s, when 91 of the county's bridges still in the inventory were built, which is 23.9% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1966) matches the Pennsylvania average (1970).

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

The 5 Pennsylvania counties nearest Lehigh County in number of bridges, with their condition splits. Its 11.3% Poor share is the 3rd-lowest of these 6. Its average build year of 1966 against a peer-group mean of 1971 is 5 years older.

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

Bridge inventory size and condition shares for Lehigh County and the 5 Pennsylvania counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Bradford County	399	43.4%	46.6%	10%	1971
Delaware County	387	24.5%	63.6%	11.9%	1968
Lehigh County (this page)	381	29.4%	59.3%	11.3%	1966
Butler County	378	29.9%	55.8%	14.3%	1975
Schuylkill County	368	20.4%	53%	26.6%	1961
Centre County	367	48%	46%	6%	1982

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

Similar inventory size

Nearest county inventories outside PA (381 bridges here).

Baldwin County, AL · 381 bridges
Obion County, TN · 381 bridges
Jasper County, IA · 382 bridges
Orleans County, LA · 382 bridges

Similar average build year

Nearest mean year-built outside PA (1966 here).

Butler County, KS · avg 1966 · 591 bridges
Grafton County, NH · avg 1966 · 544 bridges
Queens County, NY · avg 1966 · 514 bridges
Osage County, OK · avg 1966 · 366 bridges

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

All 381 Good 112 Fair 226 Poor 43

All bridges (381)

Sort:

Lehigh County Bridge Snapshot

Condition distribution

Lehigh County's Poor-condition bridges carry 224,278 vehicle crossings a day

61.4% of Lehigh County's bridges have passed the 50-year mark

One structure carries 34% of the county's Poor-condition bridge traffic

How Lehigh 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 (381)

SR 4009 (LR 39057)

DEVONSHIRE ROAD

ASH LANE

SPRINGHOUSE ROAD

GUN CLUB ROAD

LEHIGH PARKWAY E.

WALNUT STREET

HAMILTON STREET

SR 4019 (LR 39063)

SR 2029(LR.39002)

SR 4040 (LR 39072)

TOWNSHIP LINE ROAD

SR 2025(LR 39005)

4TH STREET

SR 2029(LR 39002)

SR 4024 (LR 39056)

SR1004;LR39032/125

SR 2010 (LR 39109)

SR1011 (8TH AVE)

WOOD STREET

PINE STREET

US 22(LR 771)

ALLEMAENGEL RD.

SR 4004(LR 39071)

QUARRY STREET

FURNACE ROAD

RAMP AB

CENTER ST.

SR 2018(LR 39026)

SR 4027 (LR 39060)

SR 3017

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