US Bridges

State Route 37 over Atherton Avenue

Fair

Marin County, California · 04-MRN-037-13.77 · Structure no. 27 0079R

Built
1959
66 years old
Condition
Fair
inspected May 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
177 ft
3 main spans
Daily traffic
35,500
2021 count
Owner
State
State Highway Agency

About this bridge

State Route 37 over Atherton Avenue is a concrete continuous box beam or girders - multiple carrying State Route 37 over Atherton Avenue in Marin County, California. It was built in 1959, so it is 66 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 35,500 vehicles a day, roughly 4% of them trucks, projected to reach 55,000 by 2045. The structure is 177 ft (54.1 m) long and 41 ft wide. If it were closed, the detour would be 31.7 mi (51 km).

CarriesState Route 37
CrossesAtherton Avenue
Location04-MRN-037-13.77
RouteState Highway 37
Coordinates38.1052, -122.51174
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Substructure7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating77.2 US tons
Inventory rating57.9 US tons

Structure

MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length177 ft (54.1 m)
Longest span93 ft (28.4 m)
Deck width41 ft (12.4 m)
Roadway width37 ft (11.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic35,500 (2021)
Projected traffic55,000 by 2045
Trucks4%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed31.7 mi (51 km)
TollOn a free road
National Highway SystemYes

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 37 over Atherton Avenue built?

It was built in 1959, making it 66 years old in 2025.

What condition is State Route 37 over Atherton Avenue 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 37 over Atherton Avenue carry?

About 35,500 vehicles per day (2021 count), of which roughly 4% are trucks.

How long is State Route 37 over Atherton Avenue?

The structure is 177 ft (54.1 m) long with a longest span of 93 ft (28.4 m) and a deck 41 ft wide.

Who owns State Route 37 over Atherton Avenue?

It is owned by the State Highway Agency.