County profile · official public datasets

Merced County, CA

528 public highway bridges tracked in the FHWA National Bridge Inventory: 32.2% rated Good, 59.5% Fair, 8.3% Poor.

528
Public bridges: 32.2%
Good condition: 8.3%
Poor condition

The verdict

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

Merced County posts a higher-than-median Poor-condition share among rated counties in the state across large county bridge inventory.

39th
of 58 on Poor share: 8.3%
Poor-condition share: 528
public highway bridges: 1967
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.

Merced County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Merced County ranks #39 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.3%). Merced County, California contains 528 public highway bridges. Roughly 32.2% are rated “Good,” 59.5% “Fair,” and 8.3% “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

528

Public highway bridges in Merced County

Good condition

32.2%

170 of 528 rated 7-9

Fair condition

59.5%

314 of 528 rated 5-6

Poor condition

8.3%

44 of 528 rated 4 or below

In-state Poor-share rank

#39 of 58

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

Condition distribution

Share of 528 NBI-tracked bridges by lowest applicable component rating.

Good

32.2% (170)

Fair

59.5% (314)

Poor

8.3% (44)

Merced County's Poor-condition bridges carry 296,215 vehicle crossings a day

That is 9.1% of the county's reported daily bridge traffic on 8.3% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 6,732 crossings a day against 7,217 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 528 of 528 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

70.3% of Merced County's bridges have passed the 50-year mark

371 of the 528 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 32.2% 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 8.6% of the county's Poor-condition bridge traffic

STATE ROUTE 99 NB over BLACK RASCAL CANAL, built 1962, carries 25,500 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 44-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 296,215 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

9
1920s

29
1930s

35
1940s

45
1950s

58
1960s

156
1970s

56
1980s

38
1990s

24
2000s

37
2010s

37
2020s

4

What this shows Construction peaked in the 1960s, when 156 of the county's bridges still in the inventory were built, which is 29.5% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1967) matches the California average (1970).

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

The 5 California counties nearest Merced County in number of bridges, with their condition splits. Its 8.3% Poor share is the 6th-lowest of these 6. Its average build year of 1967 against a peer-group mean of 1965 is in line with the group.

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

Bridge inventory size and condition shares for Merced County and the 5 California counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Sonoma County	609	24.1%	69%	6.9%	1967
Tulare County	589	42.4%	54.2%	3.4%	1959
Merced County (this page)	528	32.2%	59.5%	8.3%	1967
Ventura County	501	55.7%	40.1%	4.2%	1969
Shasta County	492	47.6%	49.4%	3%	1967
Tehama County	450	36.9%	56.2%	6.9%	1961

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

Similar inventory size

Nearest county inventories outside CA (528 bridges here).

LaSalle County, IL · 528 bridges
Nueces County, TX · 528 bridges
New Castle County, DE · 527 bridges
Marathon County, WI · 530 bridges

Similar average build year

Nearest mean year-built outside CA (1967 here).

Allegheny County, PA · avg 1967 · 1,294 bridges
Suffolk County, MA · avg 1967 · 489 bridges
Multnomah County, OR · avg 1967 · 473 bridges
Le Flore County, OK · avg 1967 · 469 bridges

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

All 528 Good 170 Fair 314 Poor 44

Fair-condition bridges (314)

Sort:

Merced County Bridge Snapshot

Condition distribution

Merced County's Poor-condition bridges carry 296,215 vehicle crossings a day

70.3% of Merced County's bridges have passed the 50-year mark

One structure carries 8.6% of the county's Poor-condition bridge traffic

How Merced 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 (314)

STATE ROUTE 99 NB

BRADBURY ROAD

STATE ROUTE 33

STATE ROUTE 152

STATE ROUTE 165

SULTANA DRIVE

HAMMATT AVE

CRESSEY STREET

STATE ROUTE 99 SB

STATE ROUTE 99 NB

MISSION AVENUE

STATE ROUTE 99

WESTSIDE BLVD

LE GRAND ROAD

PLAINSBURG ROAD

STATE ROUTE 99

STATE ROUTE 99 SB

STATE ROUTE 99 NB

STATE ROUTE 99 SB

STATE ROUTE 99 NB

STATE ROUTE 99 SB

STATE ROUTE 99 NB

STATE ROUTE 59

STATE ROUTE 99 SB

STATE ROUTE 99 NB

ST RTE 99NB ONRAMP

STATE ROUTE 140

RIVER ROAD

SHANKS ROAD

INGOMAR GRADE

HENRY MILLER AVE

HENRY MILLER AVE

DICKENSON FERRY RD

PLAINSBURG ROAD

MCKEE ROAD

SHAFFER ROAD

CORTEZ ROAD

FRANKLIN ROAD

ARBOLEDA DRIVE

GUN CLUB RD

BRITTO ROAD

REILLY ROAD

CHARLESTON ROAD

VAN CLIEF ROAD

FRANKLIN ROAD

BUCHANAN HOLLOW RD

WHITE ROCK ROAD

PALM AVENUE

ARROYA AVENUE

DICKENSON FERRY RD

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