Total bridges
211
Public highway bridges in Colusa County
County profile · official public datasets
Colusa County, CA
211 public highway bridges tracked in the FHWA National Bridge Inventory: 40.8% rated Good, 52.1% Fair, 7.1% Poor.
- 211
- Public bridges
- 40.8%
- Good condition
- 7.1%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Colusa County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- 32nd
- of 58 on Poor share
- 7.1%
- Poor-condition share
- 211
- public highway bridges
- 1968
- 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.
Colusa County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Colusa County ranks #32 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.1%). Colusa County, California contains 211 public highway bridges. Roughly 40.8% are rated “Good,” 52.1% “Fair,” and 7.1% “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.
Good condition
40.8%
86 of 211 rated 7-9
Fair condition
52.1%
110 of 211 rated 5-6
Poor condition
7.1%
15 of 211 rated 4 or below
In-state Poor-share rank
#32 of 58
Among California counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 211 NBI-tracked bridges by lowest applicable component rating.
Good 40.8% (86)
Fair 52.1% (110)
Poor 7.1% (15)
Colusa County's Poor-condition bridges carry 6,880 vehicle crossings a day
That is 0.9% of the county's reported daily bridge traffic on 7.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 459 crossings a day against 5,083 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 211 of 211 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
66.8% of Colusa County's bridges have passed the 50-year mark
141 of the 211 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 40.8% 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 30.2% of the county's Poor-condition bridge traffic
LONE STAR ROAD over CORTINA CREEK, built 1968, carries 2,077 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 15-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 6,880 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Colusa County's bridges were built
211 bridges with a recorded construction year, grouped by decade
- 1910s 7
1910–1919
7 bridges
- 1920s 9
1920–1929
9 bridges
- 1930s 16
1930–1939
16 bridges
- 1940s 6
1940–1949
6 bridges
- 1950s 11
1950–1959
11 bridges
- 1960s
1960–1969
40 bridges
- 1970s
1970–1979
78 bridges
- 1980s 11
1980–1989
11 bridges
- 1990s 8
1990–1999
8 bridges
- 2000s 18
2000–2009
18 bridges
- 2010s 7
2010–2019
7 bridges
What this shows Construction peaked in the 1970s, when 78 of the county's bridges still in the inventory were built, which is 37% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1968) matches the California average (1970).
How Colusa County compares with California's closest counties by inventory size
The 5 California counties nearest Colusa County in number of bridges, with their condition splits. Its 7.1% Poor share is the 3rd-lowest of these 6. Its average build year of 1968 against a peer-group mean of 1965 is in line with the group.
Showing the 5 closest of 57 California counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Glenn County | 242 | 36.8% | 52.9% | 10.3% | 1954 |
| Colusa County (this page) | 211 | 40.8% | 52.1% | 7.1% | 1968 |
| Marin County | 207 | 43.5% | 46.9% | 9.7% | 1958 |
| Trinity County | 194 | 56.2% | 39.7% | 4.1% | 1977 |
| El Dorado County | 192 | 46.9% | 46.9% | 6.3% | 1975 |
| Santa Cruz County | 192 | 40.1% | 42.2% | 17.7% | 1963 |
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 Colusa 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 Colusa County, both outside California so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside CA (211 bridges here).
- Charlotte County, FL · 211 bridges
- Kemper County, MS · 211 bridges
- Pike County, MS · 211 bridges
- Barton County, MO · 211 bridges
Similar average build year
Nearest mean year-built outside CA (1968 here).
- Montgomery County, PA · avg 1968 · 828 bridges
- Providence County, RI · avg 1968 · 476 bridges
- Delaware County, PA · avg 1968 · 387 bridges
- Genesee County, MI · avg 1968 · 371 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (211)
HANKINS ROAD
PoorOver: SPRING CREEK
0.8 MI NW FROM WALNUT DR, Colusa, CA
Built 1960 Load: 14.9 t ADT: 118
LA GRANDE RD
PoorOver: GLENN-COLUSA CANAL
0.3 MI WEST DANLEY RD, Colusa, CA
Built 1940 Load: 16.2 t ADT: 42
SYCAMORE SLOUGH RD
PoorOver: SYCAMORE SLOUGH
4.3 MI NE SACHREITER RD, Colusa, CA
Built 1915 Load: 16.8 t ADT: 60
BRIM ROAD
PoorOver: BEAR CREEK
0.1 MI W BEAR VALLEY ROAD, Colusa, CA
Built 1920 Load: 16.8 t ADT: 15
COLLEGE CITY RD
PoorOver: CLARKS DITCH
WHITE ROAD, Colusa, CA
Built 1976 Load: 20.7 t ADT: 402
OLD 99W
PoorOver: STONE CORRAL CREEK
0.6 MI N MXWL-SITES RD, Colusa, CA
Built 1927 Load: 24.3 t ADT: 1,976
FOUR MILE RD
PoorOver: LOGAN CREEK
0.7 MI N OF DELEVAN RD, Colusa, CA
Built 1965 Load: 24.3 t ADT: 31
COUNTY LINE RD
PoorOver: RD 108 10P CANAL
4.6 MI EAST OF I-5, Colusa, CA
Built 1978 Load: 31.1 t ADT: 170
HAHN ROAD
PoorOver: INTERSTATE 5
03-COL-005-R10.31, Colusa, CA
Built 1967 Load: 35.6 t ADT: 500
HUSTED ROAD
PoorOver: INTERSTATE ROUTE 5
03-COL-005-R15.91, Colusa, CA
Built 1971 Load: 36.0 t ADT: 900
LONE STAR ROAD
PoorOver: CORTINA CREEK
0.7 MI SOUTH OF MEYERS RD, Colusa, CA
Built 1968 Load: 36.9 t ADT: 2,077
Read our methodology - how this data is sourced, computed, and verified.
Related
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.