US Bridges

S280-JUNIPERO Serr over Interstate 280

Fair

San Mateo County, California · 04-SM-280-M27.20L-DLC · Structure no. 35 0174K

Built
1965
60 years old
Condition
Fair
inspected February 2025
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
539 ft
6 main spans
Daily traffic
9,600
1998 count
Owner
State
State Highway Agency

About this bridge

S280-JUNIPERO Serr over Interstate 280 is a concrete continuous box beam or girders - multiple carrying S280-JUNIPERO Serr over Interstate 280 in San Mateo County, California. It was built in 1965, so it is 60 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 9,600 vehicles a day, roughly 2% of them trucks, projected to reach 14,184 by 2047. The structure is 539 ft (164.3 m) long and 37 ft wide.

Location

Open in Google Maps
CarriesS280-JUNIPERO Serr
CrossesInterstate 280
Location04-SM-280-M27.20L-DLC
RouteInterstate 280
CountySan Mateo County
StateCalifornia
Coordinates37.70521, -122.47094
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating82.5 US tons
Inventory rating38.9 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length539 ft (164.3 m)
Longest span115 ft (35 m)
Deck width37 ft (11.3 m)
Roadway width31 ft (9.5 m)
Vertical clearance over deck16 ft (4.8 m)

Traffic and service

Average daily traffic9,600 (1998)
Projected traffic14,184 by 2047
Trucks2%
Lanes on structure2
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 S280-JUNIPERO Serr over Interstate 280 built?

It was built in 1965, making it 60 years old in 2025.

What condition is S280-JUNIPERO Serr over Interstate 280 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 S280-JUNIPERO Serr over Interstate 280 carry?

About 9,600 vehicles per day (1998 count), of which roughly 2% are trucks.

How long is S280-JUNIPERO Serr over Interstate 280?

The structure is 539 ft (164.3 m) long with a longest span of 115 ft (35 m) and a deck 37 ft wide.

Who owns S280-JUNIPERO Serr over Interstate 280?

It is owned by the State Highway Agency.