US Bridges

Redwood Blvd over Dutton Slough

Fair

Marin County, California · 0.1 MI SE Rowland Bl · Structure no. 27C0096

Built
1968
57 years old
Condition
Fair
inspected July 2024
Type
Arch - Deck
Steel
Length
31 ft
3 main spans
Daily traffic
3,641
2011 count
Owner
City
City or Municipal Highway Agency

About this bridge

Redwood Blvd over Dutton Slough is a steel arch - deck carrying Redwood Blvd over Dutton Slough in Marin County, California. It was built in 1968, so it is 57 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 5 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 3,641 vehicles a day, roughly 15% of them trucks, projected to reach 10,146 by 2046. The structure is 31 ft (9.4 m) long and 90 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesRedwood Blvd
CrossesDutton Slough
Location0.1 MI SE Rowland Bl
RouteCity Street 0
CountyMarin County
StateCalifornia
Coordinates38.08922, -122.56007
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
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure8 Very GoodNo problems noted.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating44.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeArch - Deck
MaterialSteel
DeckNot applicable
Main spans3
Design loadUnknown
Structure length31 ft (9.4 m)
Longest span10 ft (3.2 m)
Deck width90 ft (27.4 m)
Roadway width63 ft (19.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,641 (2011)
Projected traffic10,146 by 2046
Trucks15%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
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 Blvd over Dutton Slough built?

It was built in 1968, making it 57 years old in 2025.

What condition is Redwood Blvd over Dutton Slough 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 July 2024.

How much traffic does Redwood Blvd over Dutton Slough carry?

About 3,641 vehicles per day (2011 count), of which roughly 15% are trucks.

How long is Redwood Blvd over Dutton Slough?

The structure is 31 ft (9.4 m) long with a longest span of 10 ft (3.2 m) and a deck 90 ft wide.

Who owns Redwood Blvd over Dutton Slough?

It is owned by the City or Municipal Highway Agency.