Structure 27 0024 · Marin County, CA

State Route 1 over Lagunitas Creek Overflow

Carries State Route 1 over Lagunitas Creek Overflow, 04-mrn-001-28.56.

Overall conditionGood

Set by its lowest-rated component: Culvert at 7 of 9.

How ratings work
Culvertsets the rating7/9 · Good
Channelnot part of overall4/9 · Poor
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT33 FT ACROSS25 FT0ELEVATION · LENGTHS TO SCALE
Culvert 7/9

A culvert 33 ft across with 3 openings. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights, so those are drawn as typical for a culvert.

Built192997 years old
Length33.1 ft10.1 m
Daily traffic3,500counted 2021
Last inspectedMay 2024every 24 months

Location

StateCalifornia
CountyMarin
Location04-mrn-001-28.56
CarriesState Route 1
CrossesLagunitas Creek Overflow
Coordinates38.06542, -122.80506

Physical Characteristics

MaterialConcrete Continuous
DesignCulvert
Total Length33.1 ft (10.1 m)
Max Span9.8 ft (3 m)
Deck Width33.1 ft (10.1 m)
Deck Area102.0 sq m
Main Spans3
Year Built1929

Traffic

Avg Daily Traffic3,500 (2021)
Truck Traffic4%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number27 0024

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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