Total bridges
1,294
Public highway bridges in Allegheny County
County profile · official public datasets
Allegheny County, PA
1,294 public highway bridges tracked in the FHWA National Bridge Inventory: 29.6% rated Good, 61.5% Fair, 8.9% Poor.
- 1,294
- Public bridges
- 29.6%
- Good condition
- 8.9%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Allegheny County posts a better-than-median Poor-condition share among rated counties in the state across large county bridge inventory.
- Top 28%
- lowest Poor share in state
- 8.9%
- Poor-condition share
- 1,294
- public highway bridges
- 1967
- 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.
Allegheny County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Allegheny County ranks #19 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.9%). Allegheny County, Pennsylvania contains 1,294 public highway bridges. Roughly 29.6% are rated “Good,” 61.5% “Fair,” and 8.9% “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.
Good condition
29.6%
383 of 1,294 rated 7-9
Fair condition
61.5%
796 of 1,294 rated 5-6
Poor condition
8.9%
115 of 1,294 rated 4 or below
In-state Poor-share rank
#19 of 67
Among Pennsylvania counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 1,294 NBI-tracked bridges by lowest applicable component rating.
Good 29.6% (383)
Fair 61.5% (796)
Poor 8.9% (115)
Allegheny County's Poor-condition bridges carry 715,632 vehicle crossings a day
That is 4.4% of the county's reported daily bridge traffic on 8.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 6,390 crossings a day against 11,003 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 1,290 of 1,294 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
60.3% of Allegheny County's bridges have passed the 50-year mark
780 of the 1,294 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 29.6% 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 7.3% of the county's Poor-condition bridge traffic
PARKWAY EAST over OLD WM PENN HWY LEAK RUN, built 1962, carries 52,457 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 115-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 715,632 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Allegheny County's bridges were built
1,294 bridges with a recorded construction year, grouped by decade
- pre-1900 21
Built before 1900
21 bridges
- 1900s 34
1900–1909
34 bridges
- 1910s 32
1910–1919
32 bridges
- 1920s
1920–1929
75 bridges
- 1930s
1930–1939
105 bridges
- 1940s 61
1940–1949
61 bridges
- 1950s
1950–1959
176 bridges
- 1960s
1960–1969
163 bridges
- 1970s
1970–1979
156 bridges
- 1980s
1980–1989
151 bridges
- 1990s
1990–1999
86 bridges
- 2000s
2000–2009
85 bridges
- 2010s
2010–2019
125 bridges
- 2020s 24
2020–2029
24 bridges
What this shows Construction peaked in the 1950s, when 176 of the county's bridges still in the inventory were built, which is 13.6% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1967) matches the Pennsylvania average (1970).
How Allegheny County compares with Pennsylvania's closest counties by inventory size
The 5 Pennsylvania counties nearest Allegheny County in number of bridges, with their condition splits. Its 8.9% Poor share is the 1st-lowest of these 6. Its average build year of 1967 against a peer-group mean of 1965 is in line with the group.
Showing the 5 closest of 66 Pennsylvania counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Allegheny County (this page) | 1,294 | 29.6% | 61.5% | 8.9% | 1967 |
| Montgomery County | 828 | 32% | 56.5% | 11.5% | 1968 |
| Lancaster County | 801 | 30.6% | 58.2% | 11.2% | 1973 |
| Bucks County | 699 | 24.3% | 60.2% | 15.5% | 1958 |
| Chester County | 680 | 25% | 61.3% | 13.7% | 1963 |
| Berks County | 667 | 21.4% | 63.6% | 15% | 1962 |
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 Allegheny 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 Allegheny County, both outside Pennsylvania so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside PA (1,294 bridges here).
- Sedgwick County, KS · 1,333 bridges
- King County, WA · 1,238 bridges
- Oklahoma County, OK · 1,216 bridges
- Williamson County, TX · 1,170 bridges
Similar average build year
Nearest mean year-built outside PA (1967 here).
- Los Angeles County, CA · avg 1967 · 3,547 bridges
- Sonoma County, CA · avg 1967 · 609 bridges
- Merced County, CA · avg 1967 · 528 bridges
- Shasta County, CA · avg 1967 · 492 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (115)
MAPLE AVENUE
PoorOver: N CHARLES STREET
051 Maple Ave Bridge, Allegheny, PA
Built 1929 Load: 43.5 t ADT: 400
PENN OAK STREET
PoorOver: FALLEN TIMBER RUN
AT SR 51 INTERSECTION, Allegheny, PA
Built 1948 Load: 45.4 t ADT: 200
MILLTOWN ROAD
PoorOver: PLUM CREEK
1/4 MI E OF SR 2058, Allegheny, PA
Built 1979 Load: 48.1 t ADT: 1,935
WIBLE RUN RD
PoorOver: WIBLE RUN CREEK
WB01 WIBLE RUN RD NO 1, Allegheny, PA
Built 1987 Load: 48.1 t ADT: 6,583
MILROY ST
PoorOver: I-279(LR 1021)NB SB&HOV
136 Milroy St Bridge, Allegheny, PA
Built 1986 Load: 49.0 t ADT: 300
FREY RD
PoorOver: THOMPSON RUN
150 WEST OF SR 2065, Allegheny, PA
Built 1906 Load: 49.0 t ADT: 1,858
MCARDLE RDWY RD
PoorOver: SYCAMORE STREET
053 PJ McArdle Rdwy Bridg, Allegheny, PA
Built 1983 Load: 49.0 t ADT: 11,000
RP B FROM W CARSON
PoorOver: SR 0837 NB SB
Fort Pitt Bridge, Allegheny, PA
Built 1959 Load: 50.8 t ADT: 8,106
RAMP A TARENTUM BR
PoorOver: 4TH AVE RAMPD NS RR
Tarentum Bridge, Allegheny, PA
Built 1952 Load: 52.6 t ADT: 16,924
CLINTON RD
PoorOver: BR.NORTH BR.ROBINSON RUN
200 WEST OF SR 3063, Allegheny, PA
Built 1953 Load: 54.4 t ADT: 2,845
ELIZABETH ST
PoorOver: CSX RR GLOSTER ST
029 Elizabeth St Bridge, Allegheny, PA
Built 1900 Load: 58.1 t ADT: 3,000
CLINTON AVE
PoorOver: N. BR. OF ROBINSON RUN
2000N.W.OF SR 3048, Allegheny, PA
Built 1942 Load: 59.9 t ADT: 9,677
PINEVIEW DRIVE
PoorOver: GILLESPIE RUN
1000N.E.OF INTER.W/685, Allegheny, PA
Built 1930 Load: 78.0 t ADT: 1,625
SR 0050 EB WB
PoorOver: PGH & OHIO RAILWAY
@ INT. W/HOPE HOLLOW ROAD, Allegheny, PA
Built 1965 Load: 83.5 t ADT: 11,444
PA TURNPIKE (I-76)
PoorOver: PLUM CREEK
NEAR PENN HILLS, Allegheny, PA
Built 1952 Load: 89.7 t ADT: 38,689
Read our methodology - how this data is sourced, computed, and verified.
Related
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.