County profile · official public datasets

Solano County, CA

373 public highway bridges tracked in the FHWA National Bridge Inventory: 44.8% rated Good, 47.5% Fair, 7.8% Poor.

373
Public bridges: 44.8%
Good condition: 7.8%
Poor condition

The verdict

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

Solano 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.

38th
of 58 on Poor share: 7.8%
Poor-condition share: 373
public highway bridges: 1975
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.

Solano County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Solano County ranks #38 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.8%). Solano County, California contains 373 public highway bridges. Roughly 44.8% are rated “Good,” 47.5% “Fair,” and 7.8% “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

373

Public highway bridges in Solano County

Good condition

44.8%

167 of 373 rated 7-9

Fair condition

47.5%

177 of 373 rated 5-6

Poor condition

7.8%

29 of 373 rated 4 or below

In-state Poor-share rank

#38 of 58

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

Condition distribution

Share of 373 NBI-tracked bridges by lowest applicable component rating.

Good

44.8% (167)

Fair

47.5% (177)

Poor

7.8% (29)

Solano County's Poor-condition bridges carry 1,450,968 vehicle crossings a day

That is 21.7% of the county's reported daily bridge traffic on 7.8% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 50,033 crossings a day against 14,119 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 373 of 373 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

53.9% of Solano County's bridges have passed the 50-year mark

201 of the 373 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 44.8% 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 13.9% of the county's Poor-condition bridge traffic

INTERSTATE 80 over DAN WILSON CREEK, built 1951, carries 202,000 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 29-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,450,968 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

3
1910s

3
1920s

3
1930s

9
1940s

21
1950s

41
1960s

91
1970s

49
1980s

41
1990s

43
2000s

45
2010s

21
2020s

3

What this shows Construction peaked in the 1960s, when 91 of the county's bridges still in the inventory were built, which is 24.4% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1975, 5 years newer than the California average of 1970.

How Solano County compares with California's closest counties by inventory size

The 5 California counties nearest Solano County in number of bridges, with their condition splits. Its 7.8% Poor share is the 4th-lowest of these 6. Its average build year of 1975 against a peer-group mean of 1966 is 9 years newer.

Showing the 5 closest of 57 California counties eligible for comparison.

Bridge inventory size and condition shares for Solano County and the 5 California counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Humboldt County	396	38.9%	54.3%	6.8%	1968
Stanislaus County	386	30.8%	55.7%	13.5%	1956
Monterey County	377	56.8%	35.5%	7.7%	1970
Solano County (this page)	373	44.8%	47.5%	7.8%	1975
San Mateo County	361	26%	64%	10%	1967
Mendocino County	357	34.7%	57.7%	7.6%	1969

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

Similar inventory size

Nearest county inventories outside CA (373 bridges here).

Hunterdon County, NJ · 373 bridges
Marion County, OR · 373 bridges
Benton County, IA · 374 bridges
Baltimore city County, MD · 374 bridges

Similar average build year

Nearest mean year-built outside CA (1975 here).

Lane County, OR · avg 1975 · 1,010 bridges
Fulton County, GA · avg 1975 · 775 bridges
Westmoreland County, PA · avg 1975 · 620 bridges
Monroe County, NY · avg 1975 · 615 bridges

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

All 373 Good 167 Fair 177 Poor 29

Fair-condition bridges (177)

Sort:

Solano County Bridge Snapshot

Condition distribution

Solano County's Poor-condition bridges carry 1,450,968 vehicle crossings a day

53.9% of Solano County's bridges have passed the 50-year mark

One structure carries 13.9% of the county's Poor-condition bridge traffic

How Solano County compares with California's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (177)

LIBERTY ISLAND RD

INTERSTATE 680 NB

PLEASANTS VALLEY R

GRANT STREET

STATE ROUTE 12

STATE ROUTE 84

COUNTRY CLUB DR

WINTERS ROAD

HAY ROAD

SUISUN VALLEY RD

EAST SECOND ST

MANKAS CORNER RD

HILBORN ROAD

INTERSTATE 505 SB

TENNESSEE STREET

NUT TREE ROAD

SPRINGS ROAD

ALAMO DR

ROSE DRIVE

FRUITVALE RD

BYRNES RD

NORTH TEXAS STREET

E SECOND ST

GEORGIA ST

MIDWAY ROAD

GRIZZLY ISLAND RD

LEISURE TOWN RD

SILVEYVILLE RD

CORDELIA RD

COLLINSVILLE RD

STEVENSON BR RD

PENNSYLVANIA AVE

MARSHALL RD

ALAMO DR

ENGLISH HILLS RD

ALDRIDGE RD

ACCESS ROAD

BYRNES RD

INTERSTATE 80 WB

INTERSTATE 80 EB

ALLENDALE RD

INTERSTATE 80 EB

INTERSTATE 780 EB

INTERSTATE 780 WB

HARTLEY RD

INTERSTATE 680 SB

INTERSTATE 80 EB

STATE ROUTE 37

INTERSTATE 80

INTERSTATE 80 WB

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