County profile · official public datasets

Montgomery County, MD

515 public highway bridges tracked in the FHWA National Bridge Inventory: 38.8% rated Good, 56.3% Fair, 4.9% Poor.

515
Public bridges
38.8%
Good condition
4.9%
Poor condition

The verdict

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

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

14th
of 24 on Poor share
4.9%
Poor-condition share
515
public highway bridges
1978
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.

Montgomery County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Montgomery County ranks #14 of 24 Maryland counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.9%). Montgomery County, Maryland contains 515 public highway bridges. Roughly 38.8% are rated “Good,” 56.3% “Fair,” and 4.9% “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.

Total bridges

515

Public highway bridges in Montgomery County

Good condition

38.8%

200 of 515 rated 7-9

Fair condition

56.3%

290 of 515 rated 5-6

Poor condition

4.9%

25 of 515 rated 4 or below

In-state Poor-share rank

#14 of 24

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

Condition distribution

Share of 515 NBI-tracked bridges by lowest applicable component rating.

Good
38.8% (200)
Fair
56.3% (290)
Poor
4.9% (25)

Montgomery County's Poor-condition bridges carry 242,194 vehicle crossings a day

That is 1.7% of the county's reported daily bridge traffic on 4.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 9,688 crossings a day against 21,166 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 513 of 515 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

44.9% of Montgomery County's bridges have passed the 50-year mark

231 of the 515 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 38.8% 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 16.5% of the county's Poor-condition bridge traffic

CLARA BARTON PARKW over CLARA BARTON PARKWAY (SB, built 1959, carries 40,057 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 242,194 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Montgomery County's bridges were built

515 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 84 of the county's bridges still in the inventory were built, which is 16.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1978, 6 years newer than the Maryland average of 1972.

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

How Montgomery County compares with Maryland's closest counties by inventory size

The 5 Maryland counties nearest Montgomery County in number of bridges, with their condition splits. Its 4.9% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1974 is in line with the group.

Showing the 5 closest of 23 Maryland counties eligible for comparison.

Bridge inventory size and condition shares for Montgomery County and the 5 Maryland counties closest to it in inventory size
County Bridges Poor
Prince George's County 576 3.1%
Montgomery County (this page) 515 4.9%
Frederick County 486 2.7%
Anne Arundel County 389 1.5%
Baltimore city County 374 8.6%
Howard County 309 5.8%

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

Similar inventory size

Nearest county inventories outside MD (515 bridges here).

Similar average build year

Nearest mean year-built outside MD (1978 here).

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

All 515 Good 200 Fair 290 Poor 25

All bridges (515)

WITEX ROAD

Poor

Over: ROCK RUN

0.1KM S OF MACARTHUR BLVD, Montgomery, MD

Built 1980 Load: 27.8 t ADT: 500

SCHAEFFER ROAD

Poor

Over: LITTLE SENECA CREEK

0.5 MI E MD RTE 121, Montgomery, MD

Built 1925 Load: 29.5 t ADT: 437

GREENTREE ROAD

Poor

Over: BULLS RUN

0.5 MI E OF JCT SR 191, Montgomery, MD

Built 1949 Load: 37.2 t ADT: 10,816

BRINK ROAD

Poor

Over: GREAT SENECA CREEK

2.1 MILES EAST OF MD 27, Montgomery, MD

Built 1936 Load: 42.6 t ADT: 16,456

DENNIS AVENUE

Poor

Over: SLIGO CREEK TRIBUTARY

0.32 MI E OF JCT SR 97, Montgomery, MD

Built 1961 Load: 42.6 t ADT: 8,590

WEST GUDE DRIVE

Poor

Over: I-270

0.35 MILES EAST OF MD 28, Montgomery, MD

Built 1985 Load: 44.9 t ADT: 30,343

SPRING STREET

Poor

Over: CSXT RR & WMATA METRO

0.3 MI SOUTH OF MD 97, Montgomery, MD

Built 1968 Load: 49.9 t ADT: 8,204

TUCKERMAN LANE

Poor

Over: SNAKEDEN BRANCH

.5 MI W OF SEVEN LOCKS RD, Montgomery, MD

Built 1966 Load: 49.9 t ADT: 19,882

QUINCE ORCHARD ROA

Poor

Over: MUDDY BRANCH

1.8 MILES SOUTH OF MD 28, Montgomery, MD

Built 1965 Load: 66.7 t ADT: 5,297

SHADY GROVE RD EB

Poor

Over: CSXT RAILROAD

0.5 MI EAST OF MD 355, Montgomery, MD

Built 1976 Load: 76.6 t ADT: 19,679

MIDCOUNTY HWY & MI

Poor

Over: MILL CREEK

.5 MI W OF SHADY GROVE RD, Montgomery, MD

Built 1984 Load: 99.9 t ADT: 31,600

HAWKINS LANDING DR

Poor

Over: GREAT SENECA CREEK TRIBU

.06 M W OF HAWK. CREAM. R, Montgomery, MD

Built 2002 Load: 99.9 t ADT: 132

HOWELL ROAD

Poor

Over: BOOZE CREEK

900 FT. W. OF MD 191, Montgomery, MD

Built 1959 Load: 99.9 t ADT: 105

RABBITT ROAD

Poor

Over: LONG DRAUGHT BRANCH

1 MILE SOUTH OF MD 117, Montgomery, MD

Built 1982 Load: 99.9 t ADT: 1,329

CLARA BARTON PARKW

Poor

Over: CLARA BARTON PARKWAY (SB

0.1 MILES WEST OF MACARTH, Montgomery, MD

Built 1959 Load: 99.9 t ADT: 40,057

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.