US Bridges

Redwood over Laguna De Santa Rosa

Fair

Sonoma County, California · Just W/O US 101 · Structure no. 20C0068

Built
1956
69 years old, rebuilt 2002
Condition
Fair
inspected June 2023
Type
Culvert
Concrete Continuous
Length
22 ft
2 main spans
Daily traffic
2,050
2015 count
Owner
City
City or Municipal Highway Agency

About this bridge

Redwood over Laguna De Santa Rosa is a concrete continuous culvert carrying Redwood over Laguna De Santa Rosa in Sonoma County, California. It was built in 1956 and reconstructed in 2002, so it is 69 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 2,050 vehicles a day, roughly 2% of them trucks, projected to reach 4,125 by 2045. The structure is 22 ft (6.7 m) long and 69 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesRedwood
CrossesLaguna De Santa Rosa
LocationJust W/O US 101
RouteCity Street 0
CountySonoma County
StateCalifornia
Coordinates38.33686, -122.71312
Functional classUrban Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating44.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadUnknown
Structure length22 ft (6.7 m)
Longest span11 ft (3.4 m)
Deck width69 ft (21 m)
Roadway width57 ft (17.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,050 (2015)
Projected traffic4,125 by 2045
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Redwood over Laguna De Santa Rosa built?

It was built in 1956, making it 69 years old in 2025. It was reconstructed in 2002.

What condition is Redwood over Laguna De Santa Rosa in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2023.

How much traffic does Redwood over Laguna De Santa Rosa carry?

About 2,050 vehicles per day (2015 count), of which roughly 2% are trucks.

How long is Redwood over Laguna De Santa Rosa?

The structure is 22 ft (6.7 m) long with a longest span of 11 ft (3.4 m) and a deck 69 ft wide.

Who owns Redwood over Laguna De Santa Rosa?

It is owned by the City or Municipal Highway Agency.