US Bridges

N280-S1 Connector over I 280 SR 1 & Conns

Fair

San Mateo County, California · 04-SM-280-R25.26-DLC · Structure no. 35 0179G

Built
1967
58 years old
Condition
Fair
inspected February 2025
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
651 ft
6 main spans
Daily traffic
8,600
1998 count
Owner
State
State Highway Agency

About this bridge

N280-S1 Connector over I 280 SR 1 & Conns is a concrete continuous box beam or girders - multiple carrying N280-S1 Connector over I 280 SR 1 & Conns in San Mateo County, California. It was built in 1967, so it is 58 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 8,600 vehicles a day, roughly 2% of them trucks, projected to reach 29,278 by 2047. The structure is 651 ft (198.4 m) long and 28 ft wide.

Location

Open in Google Maps
CarriesN280-S1 Connector
CrossesI 280 SR 1 & Conns
Location04-SM-280-R25.26-DLC
RouteInterstate 280
CountySan Mateo County
StateCalifornia
Coordinates37.67756, -122.47072
Functional classUrban Principal Arterial - Interstate

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionFebruary 2025
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 geometry7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating82.9 US tons
Inventory rating49.6 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20 + Mod
Structure length651 ft (198.4 m)
Longest span125 ft (38.1 m)
Deck width28 ft (8.4 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,600 (1998)
Projected traffic29,278 by 2047
Trucks2%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemYes

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 N280-S1 Connector over I 280 SR 1 & Conns built?

It was built in 1967, making it 58 years old in 2025.

What condition is N280-S1 Connector over I 280 SR 1 & Conns 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 February 2025.

How much traffic does N280-S1 Connector over I 280 SR 1 & Conns carry?

About 8,600 vehicles per day (1998 count), of which roughly 2% are trucks.

How long is N280-S1 Connector over I 280 SR 1 & Conns?

The structure is 651 ft (198.4 m) long with a longest span of 125 ft (38.1 m) and a deck 28 ft wide.

Who owns N280-S1 Connector over I 280 SR 1 & Conns?

It is owned by the State Highway Agency.