County profile · official public datasets

San Francisco County, CA

143 public highway bridges tracked in the FHWA National Bridge Inventory: 34.3% rated Good, 51% Fair, 14.7% Poor.

143
Public bridges: 34.3%
Good condition: 14.7%
Poor condition

The verdict

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

San Francisco County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

56th
of 58 on Poor share: 14.7%
Poor-condition share: 143
public highway bridges: 1969
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.

San Francisco County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, San Francisco County ranks #56 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 14.7%). San Francisco County, California contains 143 public highway bridges. Roughly 34.3% are rated “Good,” 51% “Fair,” and 14.7% “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

143

Public highway bridges in San Francisco County

Good condition

34.3%

49 of 143 rated 7-9

Fair condition

51%

73 of 143 rated 5-6

Poor condition

14.7%

21 of 143 rated 4 or below

In-state Poor-share rank

#56 of 58

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

Condition distribution

Share of 143 NBI-tracked bridges by lowest applicable component rating.

Good

34.3% (49)

Fair

51% (73)

Poor

14.7% (21)

San Francisco County's Poor-condition bridges carry 1,202,345 vehicle crossings a day

That is 15.4% of the county's reported daily bridge traffic on 14.7% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 57,255 crossings a day against 43,517 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 143 of 143 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

74.1% of San Francisco County's bridges have passed the 50-year mark

106 of the 143 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 34.3% 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 14.1% of the county's Poor-condition bridge traffic

NB AND SB RTE 280 over LYELL STREET, built 1964, carries 170,000 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 21-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,202,345 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

1
1920s

2
1930s

22
1940s

2
1950s

27
1960s

43
1970s

9
1990s

4
2000s

9
2010s

23
2020s

1

What this shows Construction peaked in the 1960s, when 43 of the county's bridges still in the inventory were built, which is 30.1% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1969) matches the California average (1970).

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

The 5 California counties nearest San Francisco County in number of bridges, with their condition splits. Its 14.7% Poor share is the 6th-lowest of these 6. Its average build year of 1969 against a peer-group mean of 1967 is in line with the group.

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

Bridge inventory size and condition shares for San Francisco County and the 5 California counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Napa County	158	45.6%	50%	4.4%	1961
San Francisco County (this page)	143	34.3%	51%	14.7%	1969
Nevada County	135	45.2%	40.7%	14.1%	1972
Lake County	129	30.2%	62%	7.8%	1970
Yuba County	127	37.8%	55.9%	6.3%	1967
Tuolumne County	125	36%	56.8%	7.2%	1964

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

Similar inventory size

Nearest county inventories outside CA (143 bridges here).

Franklin County, AR · 143 bridges
Woodson County, KS · 143 bridges
Adair County, KY · 143 bridges
Casey County, KY · 143 bridges

Similar average build year

Nearest mean year-built outside CA (1969 here).

Cook County, IL · avg 1969 · 1,721 bridges
Cuyahoga County, OH · avg 1969 · 871 bridges
Somerset County, PA · avg 1969 · 454 bridges
Lewis County, WA · avg 1969 · 419 bridges

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

All 143 Good 49 Fair 73 Poor 21

Poor-condition bridges (21)

Sort:

San Francisco County Bridge Snapshot

Condition distribution

San Francisco County's Poor-condition bridges carry 1,202,345 vehicle crossings a day

74.1% of San Francisco County's bridges have passed the 50-year mark

One structure carries 14.1% of the county's Poor-condition bridge traffic

How San Francisco 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

Poor-condition bridges (21)

TREASURE ISD RD SB

EVANS AVE

I280S OFF-MONTEREY

THIRD STREET

TREASURE ISD RD NB

GENEVA AVE

I 280

NB AND SB RTE 280

INTERSTATE 280

ALEMANY BLVD NB

PAULDING/JUDSON ST

18TH STREET

WILLIAMS AVENUE

BAYSHORE BLVD

101 AND 280

S280-S101 CONNECTR

I 280 - 101S (WU)

I 280 S AU LINE

I 280 N AL LINE

MARIPOSA ST

JUSTIN DRIVE

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