US Bridges

U.S. Highway 101 over Blanken Ave

Fair

San Francisco County, California · 04-SF-101-0.18-SF · Structure no. 34 0061

Built
1954
71 years old
Condition
Fair
inspected December 2023
Type
Box Beam or Girders - Multiple
Concrete
Length
44 ft
1 main span
Daily traffic
199,000
2019 count
Owner
State
State Highway Agency

About this bridge

U.S. Highway 101 over Blanken Ave is a concrete box beam or girders - multiple carrying U.S. Highway 101 over Blanken Ave in San Francisco County, California. It was built in 1954, so it is 71 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 199,000 vehicles a day, roughly 5% of them trucks, projected to reach 258,116 by 2042. The structure is 44 ft (13.4 m) long and 114 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesU.S. Highway 101
CrossesBlanken Ave
Location04-SF-101-0.18-SF
RouteU.S. Route 101
CountySan Francisco County
StateCalifornia
Coordinates37.71081, -122.39529
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionDecember 2023
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
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.3 US tons
Inventory rating40.3 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete
DeckNot applicable
Main spans1
Design loadUnknown
Structure length44 ft (13.4 m)
Longest span40 ft (12.2 m)
Deck width114 ft (34.8 m)
Roadway width114 ft (34.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic199,000 (2019)
Projected traffic258,116 by 2042
Trucks5%
Lanes on structure8
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 U.S. Highway 101 over Blanken Ave built?

It was built in 1954, making it 71 years old in 2025.

What condition is U.S. Highway 101 over Blanken Ave 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 December 2023.

How much traffic does U.S. Highway 101 over Blanken Ave carry?

About 199,000 vehicles per day (2019 count), of which roughly 5% are trucks.

How long is U.S. Highway 101 over Blanken Ave?

The structure is 44 ft (13.4 m) long with a longest span of 40 ft (12.2 m) and a deck 114 ft wide.

Who owns U.S. Highway 101 over Blanken Ave?

It is owned by the State Highway Agency.