US Bridges

Muir Woods RD over Redwood Creek

Fair

Marin County, California · 2.0 MI N of SR 1 · Structure no. 27C0107

Built
1946
79 years old
Condition
Fair
inspected July 2023
Type
Tee Beam
Concrete
Length
22 ft
1 main span
Daily traffic
2,090
2001 count
Owner
County
County Highway Agency

About this bridge

Muir Woods RD over Redwood Creek is a concrete tee beam carrying Muir Woods RD over Redwood Creek in Marin County, California. It was built in 1946, so it is 79 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 2,090 vehicles a day, roughly 2% of them trucks, projected to reach 3,180 by 2041. The structure is 22 ft (6.6 m) long and 27 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesMuir Woods RD
CrossesRedwood Creek
Location2.0 MI N of SR 1
RouteCounty Highway 0
CountyMarin County
StateCalifornia
Coordinates37.88857, -122.56733
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating31.7 US tons
Inventory rating24.7 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length22 ft (6.6 m)
Longest span21 ft (6.3 m)
Deck width27 ft (8.2 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,090 (2001)
Projected traffic3,180 by 2041
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Muir Woods RD over Redwood Creek built?

It was built in 1946, making it 79 years old in 2025.

What condition is Muir Woods RD over Redwood Creek 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 2023.

How much traffic does Muir Woods RD over Redwood Creek carry?

About 2,090 vehicles per day (2001 count), of which roughly 2% are trucks.

How long is Muir Woods RD over Redwood Creek?

The structure is 22 ft (6.6 m) long with a longest span of 21 ft (6.3 m) and a deck 27 ft wide.

Who owns Muir Woods RD over Redwood Creek?

It is owned by the County Highway Agency.