US Bridges

State Route 1 over Olema Creek

Fair

Marin County, California · 04-MRN-001-22.81 · Structure no. 27 0020

Built
1928
97 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
54 ft
3 main spans
Daily traffic
2,900
2020 count
Owner
State
State Highway Agency

About this bridge

State Route 1 over Olema Creek is a concrete continuous slab carrying State Route 1 over Olema Creek in Marin County, California. It was built in 1928, so it is 97 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 2,900 vehicles a day, roughly 1% of them trucks, projected to reach 4,778 by 2042. The structure is 54 ft (16.5 m) long and 23 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesState Route 1
CrossesOlema Creek
Location04-MRN-001-22.81
RouteState Highway 1
CountyMarin County
StateCalifornia
Coordinates37.99785, -122.75502
Functional classRural 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 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 geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65.4 US tons
Inventory rating39.2 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 15
Structure length54 ft (16.5 m)
Longest span16 ft (4.9 m)
Deck width23 ft (7 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,900 (2020)
Projected traffic4,778 by 2042
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 State Route 1 over Olema Creek built?

It was built in 1928, making it 97 years old in 2025.

What condition is State Route 1 over Olema 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 May 2024.

How much traffic does State Route 1 over Olema Creek carry?

About 2,900 vehicles per day (2020 count), of which roughly 1% are trucks.

How long is State Route 1 over Olema Creek?

The structure is 54 ft (16.5 m) long with a longest span of 16 ft (4.9 m) and a deck 23 ft wide.

Who owns State Route 1 over Olema Creek?

It is owned by the State Highway Agency.