US Bridges

Alexander Ave over Bunker Road

Fair

Marin County, California · 0.3 KM East of RTE 101 · Structure no. 27C0053

Built
1937
88 years old
Condition
Fair
inspected March 2024
Type
Arch - Deck
Concrete
Length
32 ft
1 main span
Daily traffic
7,201
2024 count
Owner
Toll Authority
Local Toll Authority

About this bridge

Alexander Ave over Bunker Road is a concrete arch - deck carrying Alexander Ave over Bunker Road in Marin County, California. It was built in 1937, so it is 88 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 7,201 vehicles a day, roughly 2% of them trucks, projected to reach 9,000 by 2044. The structure is 32 ft (9.8 m) long. If it were closed, the detour would be 6.8 mi (11 km).

Location

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CarriesAlexander Ave
CrossesBunker Road
Location0.3 KM East of RTE 101
RouteCounty Highway 0
CountyMarin County
StateCalifornia
Coordinates37.83801, -122.48303
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
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating96.8 US tons
Inventory rating74.6 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadH 15
Structure length32 ft (9.8 m)
Longest span24 ft (7.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,201 (2024)
Projected traffic9,000 by 2044
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerLocal Toll Authority
Maintained byLocal Toll Authority
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Alexander Ave over Bunker Road built?

It was built in 1937, making it 88 years old in 2025.

What condition is Alexander Ave over Bunker Road 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 March 2024.

How much traffic does Alexander Ave over Bunker Road carry?

About 7,201 vehicles per day (2024 count), of which roughly 2% are trucks.

How long is Alexander Ave over Bunker Road?

The structure is 32 ft (9.8 m) long with a longest span of 24 ft (7.3 m).

Who owns Alexander Ave over Bunker Road?

It is owned by the Local Toll Authority.