County profile · official public datasets

Howard County, MD

309 public highway bridges tracked in the FHWA National Bridge Inventory: 35.9% rated Good, 58.3% Fair, 5.8% Poor.

309
Public bridges
35.9%
Good condition
5.8%
Poor condition

The verdict

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

Howard 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.

16th
of 24 on Poor share
5.8%
Poor-condition share
309
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.

Howard County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Howard County ranks #16 of 24 Maryland counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 5.8%). Howard County, Maryland contains 309 public highway bridges. Roughly 35.9% are rated “Good,” 58.3% “Fair,” and 5.8% “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

309

Public highway bridges in Howard County

Good condition

35.9%

111 of 309 rated 7-9

Fair condition

58.3%

180 of 309 rated 5-6

Poor condition

5.8%

18 of 309 rated 4 or below

In-state Poor-share rank

#16 of 24

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

Condition distribution

Share of 309 NBI-tracked bridges by lowest applicable component rating.

Good
35.9% (111)
Fair
58.3% (180)
Poor
5.8% (18)

Howard County's Poor-condition bridges carry 46,181 vehicle crossings a day

That is 0.5% of the county's reported daily bridge traffic on 5.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 2,566 crossings a day against 20,094 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 308 of 309 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

46.9% of Howard County's bridges have passed the 50-year mark

145 of the 309 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 35.9% 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 23.7% of the county's Poor-condition bridge traffic

TAMAR DRIVE over UNNAMED STREAM, built 1970, carries 10,941 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 18-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 46,181 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Howard County's bridges were built

309 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 81 of the county's bridges still in the inventory were built, which is 26.2% of those with a recorded year. That cohort is now 45 to 54 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 Howard County compares with Maryland's closest counties by inventory size

The 5 Maryland counties nearest Howard County in number of bridges, with their condition splits. Its 5.8% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1969 is 9 years newer.

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

Bridge inventory size and condition shares for Howard County and the 5 Maryland counties closest to it in inventory size
County Bridges Poor
Anne Arundel County 389 1.5%
Baltimore city County 374 8.6%
Howard County (this page) 309 5.8%
Washington County 300 4.7%
Harford County 275 4.7%
Allegany County 245 6.1%

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

Similar inventory size

Nearest county inventories outside MD (309 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 309 Good 111 Fair 180 Poor 18

Poor-condition bridges (18)

OLD MONTGOMERY RD

Poor

Over: LITTLE PATUXENT RIVER

0.5 MI W OF US RTE 29, Howard, MD

Built 1935 Load: 10.0 t ADT: 10

TIBER ALLEY

Poor

Over: TIBER RIVER

0.01 MI S MAIN STREET, Howard, MD

Built 1935 Load: 12.2 t ADT: 45

DAISY ROAD

Poor

Over: LITTLE CATTAIL CREEK

0.3 MI N JENNINGS CHAPEL, Howard, MD

Built 1935 Load: 12.7 t ADT: 1,525

SANDCHAIN ROAD

Poor

Over: LITTLE PATUXENT RIVER

.03 MI W OF YOUNGHEART, Howard, MD

Built 1972 Load: 21.3 t ADT: 1,209

PFEFFERKORN ROAD

Poor

Over: MIDDLE PATUXENT RIVER

1 MI S OF MD RTE 144, Howard, MD

Built 1935 Load: 24.9 t ADT: 1,116

UNION CHAPEL ROAD

Poor

Over: CATTAIL CREEK

0.5 MI E OF DAISY RD, Howard, MD

Built 1955 Load: 26.8 t ADT: 1,052

HENRYTON ROAD

Poor

Over: TRIBUTARY OF PATAPSCO RI

2.09 MI N OF MD RTE 99, Howard, MD

Built 1925 Load: 29.0 t ADT: 1,113

HENRYTON ROAD

Poor

Over: TRIBUTARY OF PATAPSCO RI

1.24 MI N OF MD RTE 99, Howard, MD

Built 1925 Load: 36.3 t ADT: 1,180

SENECA ROAD

Poor

Over: BEAVER RUN BRANCH

0.5 MI E OF US RTE 29, Howard, MD

Built 1960 Load: 38.5 t ADT: 896

BROWNS BRIDGE ROAD

Poor

Over: PATUXENT RIVER

1.4 MI E OF MD 650, Howard, MD

Built 1953 Load: 39.9 t ADT: 5,772

TAMAR DRIVE

Poor

Over: UNNAMED STREAM

0.1 MI E PHELPS LUCK, Howard, MD

Built 1970 Load: 60.8 t ADT: 10,941

COLUMBIA ROAD

Poor

Over: PLUMTREE BRANCH

0.8 MI. NORTH OF MD. 108, Howard, MD

Built 1987 Load: 75.7 t ADT: 8,641

BELMONT WOODS ROAD

Poor

Over: ROCKBURN BRANCH

0.1 MI W OF I-95, Howard, MD

Built 1950 Load: 77.1 t ADT: 100

BROKEN LAND PARKWA

Poor

Over: TRIB LITTLE PATUXENT R

At Cradlerock Way, Howard, MD

Built 1972 Load: 79.8 t ADT: 10,000

ILCHESTER ROAD

Poor

Over: BONNIE BRANCH

AT BONNIE BRANCH RD, Howard, MD

Built 1945 Load: 99.9 t ADT: 1,281

QUARTER STAFF ROAD

Poor

Over: TRIB TO LITTLE PATUXENT

1000 NW of Martin Ln, Howard, MD

Built 1972 Load: 99.9 t ADT: 300

SUMMER HOLLOW LN

Poor

Over: UNNAMED STREAM

1/8 MI S OF MD 108, Howard, MD

Built 1972 Load: 99.9 t ADT: 500

WESLEY LANE

Poor

Over: BRANCH OF DEEP RUN

50 east of MD 103, Howard, MD

Built 1972 Load: 99.9 t ADT: 500

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.