US Bridges

US101N-I 280S (wl) over 280/101 Interchange

Fair

San Francisco County, California · 04-SF-101-1.79-SF · Structure no. 34 0135G

Built
1960
65 years old
Condition
Fair
inspected March 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
1,579 ft
16 main spans
Daily traffic
80,000
2019 count
Owner
State
State Highway Agency

About this bridge

US101N-I 280S (wl) over 280/101 Interchange is a concrete continuous box beam or girders - multiple carrying US101N-I 280S (wl) over 280/101 Interchange in San Francisco County, California. It was built in 1960, so it is 65 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 80,000 vehicles a day, roughly 3% of them trucks, projected to reach 107,238 by 2044. The structure is 1,579 ft (481.4 m) long and 37 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesUS101N-I 280S (wl)
Crosses280/101 Interchange
Location04-SF-101-1.79-SF
RouteU.S. Route 101
CountySan Francisco County
StateCalifornia
Coordinates37.73297, -122.40499
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans16
Design loadUnknown
Structure length1,579 ft (481.4 m)
Longest span121 ft (36.9 m)
Deck width37 ft (11.4 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deck15 ft (4.6 m)

Traffic and service

Average daily traffic80,000 (2019)
Projected traffic107,238 by 2044
Trucks3%
Lanes on structure1
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed3.1 mi (5 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 US101N-I 280S (wl) over 280/101 Interchange built?

It was built in 1960, making it 65 years old in 2025.

What condition is US101N-I 280S (wl) over 280/101 Interchange 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 March 2024.

How much traffic does US101N-I 280S (wl) over 280/101 Interchange carry?

About 80,000 vehicles per day (2019 count), of which roughly 3% are trucks.

How long is US101N-I 280S (wl) over 280/101 Interchange?

The structure is 1,579 ft (481.4 m) long with a longest span of 121 ft (36.9 m) and a deck 37 ft wide.

Who owns US101N-I 280S (wl) over 280/101 Interchange?

It is owned by the State Highway Agency.