US Bridges

Foster City Blvd over Foster City Lagoon

Fair

San Mateo County, California · East of Bounty DR · Structure no. 35C0070L

Built
1966
59 years old
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
504 ft
5 main spans
Daily traffic
5,042
2022 count
Owner
City
City or Municipal Highway Agency

About this bridge

Foster City Blvd over Foster City Lagoon is a concrete continuous box beam or girders - multiple carrying Foster City Blvd over Foster City Lagoon in San Mateo County, California. It was built in 1966, so it is 59 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 5,042 vehicles a day, roughly 8% of them trucks, projected to reach 9,024 by 2041. The structure is 504 ft (153.6 m) long and 32 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesFoster City Blvd
CrossesFoster City Lagoon
LocationEast of Bounty DR
RouteCity Street 0
CountySan Mateo County
StateCalifornia
Coordinates37.55518, -122.25824
Functional classUrban Other Principal Arterial

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.1 US tons
Inventory rating45 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length504 ft (153.6 m)
Longest span100 ft (30.5 m)
Deck width32 ft (9.8 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,042 (2022)
Projected traffic9,024 by 2041
Trucks8%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Foster City Blvd over Foster City Lagoon built?

It was built in 1966, making it 59 years old in 2025.

What condition is Foster City Blvd over Foster City Lagoon 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 Foster City Blvd over Foster City Lagoon carry?

About 5,042 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is Foster City Blvd over Foster City Lagoon?

The structure is 504 ft (153.6 m) long with a longest span of 100 ft (30.5 m) and a deck 32 ft wide.

Who owns Foster City Blvd over Foster City Lagoon?

It is owned by the City or Municipal Highway Agency.