US Bridges

101 and 280 over 280/101 Interchange

Poor

San Francisco County, California · 04-SF-101-1.63-SF · Structure no. 34 0070

Built
1960
65 years old
Condition
Poor
inspected March 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
1,634 ft
18 main spans
Daily traffic
153,800
2019 count
Owner
State
State Highway Agency

About this bridge

101 and 280 over 280/101 Interchange is a concrete continuous box beam or girders - multiple carrying 101 and 280 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 poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 153,800 vehicles a day, roughly 2% of them trucks, projected to reach 379,087 by 2041. The structure is 1,634 ft (498 m) long and 38 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries101 and 280
Crosses280/101 Interchange
Location04-SF-101-1.63-SF
RouteU.S. Route 101
CountySan Francisco County
StateCalifornia
Coordinates37.73094, -122.40382
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, 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 geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment6: Equal to present minimum criteria
Operating rating83.6 US tons
Inventory rating50.4 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans18
Design loadHS 20
Structure length1,634 ft (498 m)
Longest span93 ft (28.4 m)
Deck width38 ft (11.5 m)
Roadway width34 ft (10.3 m)
Vertical clearance over deck14 ft (4.3 m)

Traffic and service

Average daily traffic153,800 (2019)
Projected traffic379,087 by 2041
Trucks2%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesThird level (interchange)
CrossesHighway
Detour if closed1.9 mi (3 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$9.6 million (2024 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was 101 and 280 over 280/101 Interchange built?

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

What condition is 101 and 280 over 280/101 Interchange in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in March 2024.

How much traffic does 101 and 280 over 280/101 Interchange carry?

About 153,800 vehicles per day (2019 count), of which roughly 2% are trucks.

How long is 101 and 280 over 280/101 Interchange?

The structure is 1,634 ft (498 m) long with a longest span of 93 ft (28.4 m) and a deck 38 ft wide.

Who owns 101 and 280 over 280/101 Interchange?

It is owned by the State Highway Agency.