US Bridges

U.S. Highway 101 over Caltrain UP RR Sierra Pt

Fair

San Mateo County, California · 04-SM-101-23.66-BSBN · Structure no. 35 0130

Built
1956
69 years old, rebuilt 1969
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
616 ft
11 main spans
Daily traffic
196,000
2009 count
Owner
State
State Highway Agency

About this bridge

U.S. Highway 101 over Caltrain UP RR Sierra Pt is a steel stringer/multi-beam or girder carrying U.S. Highway 101 over Caltrain UP RR Sierra Pt in San Mateo County, California. It was built in 1956 and reconstructed in 1969, so it is 69 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 196,000 vehicles a day, roughly 4% of them trucks, projected to reach 243,117 by 2040. The structure is 616 ft (187.8 m) long and 116 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesU.S. Highway 101
CrossesCaltrain UP RR Sierra Pt
Location04-SM-101-23.66-BSBN
RouteU.S. Route 101
CountySan Mateo County
StateCalifornia
Coordinates37.67299, -122.39007
Functional classUrban Principal Arterial - Other Freeway or Expressway

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 inspectionApril 2023
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 rating54.2 US tons
Inventory rating41.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans11
Design loadHS 20
Structure length616 ft (187.8 m)
Longest span104 ft (31.7 m)
Deck width116 ft (35.4 m)
Roadway width110 ft (33.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic196,000 (2009)
Projected traffic243,117 by 2040
Trucks4%
Lanes on structure8
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate 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 U.S. Highway 101 over Caltrain UP RR Sierra Pt built?

It was built in 1956, making it 69 years old in 2025. It was reconstructed in 1969.

What condition is U.S. Highway 101 over Caltrain UP RR Sierra Pt 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 U.S. Highway 101 over Caltrain UP RR Sierra Pt carry?

About 196,000 vehicles per day (2009 count), of which roughly 4% are trucks.

How long is U.S. Highway 101 over Caltrain UP RR Sierra Pt?

The structure is 616 ft (187.8 m) long with a longest span of 104 ft (31.7 m) and a deck 116 ft wide.

Who owns U.S. Highway 101 over Caltrain UP RR Sierra Pt?

It is owned by the State Highway Agency.