US Bridges

U.S. Highway 101 over Airport Boulevard

Fair

San Mateo County, California · 04-SM-101-21.69-SSF · Structure no. 35 0119

Built
1947
78 years old, rebuilt 1975
Condition
Fair
inspected April 2023
Type
Tee Beam
Concrete Continuous
Length
116 ft
3 main spans
Daily traffic
188,000
2009 count
Owner
State
State Highway Agency

About this bridge

U.S. Highway 101 over Airport Boulevard is a concrete continuous tee beam carrying U.S. Highway 101 over Airport Boulevard in San Mateo County, California. It was built in 1947 and reconstructed in 1975, so it is 78 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 188,000 vehicles a day, roughly 4% of them trucks, projected to reach 267,887 by 2040. The structure is 116 ft (35.4 m) long and 168 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesU.S. Highway 101
CrossesAirport Boulevard
Location04-SM-101-21.69-SSF
RouteU.S. Route 101
CountySan Mateo County
StateCalifornia
Coordinates37.64983, -122.40647
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 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 alignment8: Equal to present desirable criteria
Operating rating67.1 US tons
Inventory rating35.7 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length116 ft (35.4 m)
Longest span46 ft (14.1 m)
Deck width168 ft (51.2 m)
Roadway width164 ft (50 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic188,000 (2009)
Projected traffic267,887 by 2040
Trucks4%
Lanes on structure10
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 Airport Boulevard built?

It was built in 1947, making it 78 years old in 2025. It was reconstructed in 1975.

What condition is U.S. Highway 101 over Airport Boulevard 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 U.S. Highway 101 over Airport Boulevard carry?

About 188,000 vehicles per day (2009 count), of which roughly 4% are trucks.

How long is U.S. Highway 101 over Airport Boulevard?

The structure is 116 ft (35.4 m) long with a longest span of 46 ft (14.1 m) and a deck 168 ft wide.

Who owns U.S. Highway 101 over Airport Boulevard?

It is owned by the State Highway Agency.