County profile · official public datasets

Washington County, OR

326 public highway bridges tracked in the FHWA National Bridge Inventory: 35.6% rated Good, 62% Fair, 2.5% Poor.

326
Public bridges: 35.6%
Good condition: 2.5%
Poor condition

The verdict

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

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

Top 31%
lowest Poor share in state: 2.5%
Poor-condition share: 326
public highway bridges: 1983
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.

Washington County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Washington County ranks #11 of 36 Oregon counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.5%). Washington County, Oregon contains 326 public highway bridges. Roughly 35.6% are rated “Good,” 62% “Fair,” and 2.5% “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

326

Public highway bridges in Washington County

Good condition

35.6%

116 of 326 rated 7-9

Fair condition

62%

202 of 326 rated 5-6

Poor condition

2.5%

8 of 326 rated 4 or below

In-state Poor-share rank

#11 of 36

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

Condition distribution

Share of 326 NBI-tracked bridges by lowest applicable component rating.

Good

35.6% (116)

Fair

62% (202)

Poor

2.5% (8)

Washington County's Poor-condition bridges carry 54,681 vehicle crossings a day

That is 1.1% of the county's reported daily bridge traffic on 2.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 6,835 crossings a day against 10,980 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 326 of 326 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

38.3% of Washington County's bridges have passed the 50-year mark

125 of the 326 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 35.6% 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 35.6% of the county's Poor-condition bridge traffic

ALLEN BLVD over HWY 144, built 1981, carries 19,471 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 8-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 54,681 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

5
1930s

6
1940s

10
1950s

24
1960s

41
1970s

68
1980s

38
1990s

37
2000s

57
2010s

25
2020s

15

What this shows Construction peaked in the 1970s, when 68 of the county's bridges still in the inventory were built, which is 20.9% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1983, 8 years newer than the Oregon average of 1975.

How Washington County compares with Oregon's closest counties by inventory size

The 5 Oregon counties nearest Washington County in number of bridges, with their condition splits. Its 2.5% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1975 is 8 years newer.

Showing the 5 closest of 35 Oregon counties eligible for comparison.

Bridge inventory size and condition shares for Washington County and the 5 Oregon counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Jackson County	401	34.2%	64.3%	1.5%	1976
Marion County	373	21.2%	74.5%	4.3%	1971
Clackamas County	367	31.1%	66.5%	2.5%	1975
Washington County (this page)	326	35.6%	62%	2.5%	1983
Umatilla County	321	31.5%	64.5%	4%	1973
Coos County	254	40.9%	55.9%	3.1%	1978

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

Similar inventory size

Nearest county inventories outside OR (326 bridges here).

Miami County, KS · 326 bridges
Montgomery County, KS · 326 bridges
Merrimack County, NH · 326 bridges
St. Clair County, MI · 327 bridges

Similar average build year

Nearest mean year-built outside OR (1983 here).

Dallas County, TX · avg 1983 · 3,230 bridges
Bexar County, TX · avg 1983 · 2,342 bridges
Sedgwick County, KS · avg 1983 · 1,333 bridges
Will County, IL · avg 1983 · 649 bridges

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

All 326 Good 116 Fair 202 Poor 8

All bridges (326)

Sort:

Washington County Bridge Snapshot

Condition distribution

Washington County's Poor-condition bridges carry 54,681 vehicle crossings a day

38.3% of Washington County's bridges have passed the 50-year mark

One structure carries 35.6% of the county's Poor-condition bridge traffic

How Washington County compares with Oregon'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 (326)

SW MURRAY BLVD SB

Cornell Road

OLD TV HWY #47

REIN ROAD

US 26 (HWY 047)

Fern Flat Rd.

170TH AVE

BOHMANN PARKWAY

NICOL RD

SW 229th AVE

Hwy 029

PADGETT ROAD

LOMBARD EXTENSION

OR 217 (HWY 144)

I-5 (HWY 001) CON

72ND AVE

HWY 141

185TH AVE

FERN FLAT ROAD

SW 86TH AVE

EVERS ROAD

HWY 91 SB

OR 6 (Hwy 037)

OR 99W(HWY 001W)NB

US 26 (HWY 047) WB

Hwy 29

HWY 91

DENNY RD & RAMP

SW 92ND AVE

US 26 (Hwy 047)

CORNELIUS PASS RD

HAINES ROAD

COCHRAN RD

HWY 91

TIGARD STREET

SW WILSHIRE

HWY 141

OR 99W(HWY 91)SB

I-5 (HWY 001)

OR 47 (Hwy 102)

US 26 (Hwy 047)

MURRAY BLVD CO

MOUNTAINDALE ROAD

NW DAIRY CREEK RD

OLD TV HWY #47

OR 99W (HWY 91)

I-5 (HWY 001)

OR 217 (HWY 144)

OR 217 (HWY 144)

OR 6 (Hwy 037)

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