US Bridges

S101-SFO Airpt Off over U.S. Highway 101

Fair

San Mateo County, California · 04-SM-101-19.26 · Structure no. 35 0275K

Built
1987
38 years old
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
1,619 ft
10 main spans
Daily traffic
15,900
1998 count
Owner
State
State Highway Agency

About this bridge

S101-SFO Airpt Off over U.S. Highway 101 is a prestressed concrete continuous box beam or girders - multiple carrying S101-SFO Airpt Off over U.S. Highway 101 in San Mateo County, California. It was built in 1987, so it is 38 years old, younger 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 6 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 15,900 vehicles a day, roughly 2% of them trucks, projected to reach 27,255 by 2040. The structure is 1,619 ft (493.4 m) long and 41 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesS101-SFO Airpt Off
CrossesU.S. Highway 101
Location04-SM-101-19.26
RouteU.S. Route 101
CountySan Mateo County
StateCalifornia
Coordinates37.614, -122.39528
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans10 (+6 approach)
Design loadHS 20 + Mod
Structure length1,619 ft (493.4 m)
Longest span246 ft (75 m)
Deck width41 ft (12.6 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deck18 ft (5.5 m)

Traffic and service

Average daily traffic15,900 (1998)
Projected traffic27,255 by 2040
Trucks2%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate 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 S101-SFO Airpt Off over U.S. Highway 101 built?

It was built in 1987, making it 38 years old in 2025.

What condition is S101-SFO Airpt Off over U.S. Highway 101 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 April 2023.

How much traffic does S101-SFO Airpt Off over U.S. Highway 101 carry?

About 15,900 vehicles per day (1998 count), of which roughly 2% are trucks.

How long is S101-SFO Airpt Off over U.S. Highway 101?

The structure is 1,619 ft (493.4 m) long with a longest span of 246 ft (75 m) and a deck 41 ft wide.

Who owns S101-SFO Airpt Off over U.S. Highway 101?

It is owned by the State Highway Agency.