US Bridges

I380 NB On-Ramp over US 101

Fair

San Mateo County, California · Span 9 Hinge to Bent 19 · Structure no. 35C0180K

Built
1996
29 years old
Condition
Fair
inspected January 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
1,325 ft
12 main spans
Daily traffic
27,142
2010 count
Owner
Local
Other Local Agency

About this bridge

I380 NB On-Ramp over US 101 is a prestressed concrete continuous box beam or girders - multiple carrying I380 NB On-Ramp over US 101 in San Mateo County, California. It was built in 1996, so it is 29 years old, younger 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 27,142 vehicles a day, roughly 5% of them trucks, projected to reach 30,034 by 2042. The structure is 1,325 ft (403.8 m) long and 29 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesI380 NB On-Ramp
CrossesUS 101
LocationSpan 9 Hinge to Bent 19
RouteCounty Highway 0
CountySan Mateo County
StateCalifornia
Coordinates37.61502, -122.39461
Functional classUrban Local

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
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
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans12
Design loadHS 20 + Mod
Structure length1,325 ft (403.8 m)
Longest span144 ft (44 m)
Deck width29 ft (8.8 m)
Roadway width26 ft (7.8 m)
Vertical clearance over deck17 ft (5.2 m)

Traffic and service

Average daily traffic27,142 (2010)
Projected traffic30,034 by 2042
Trucks5%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local 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 I380 NB On-Ramp over US 101 built?

It was built in 1996, making it 29 years old in 2025.

What condition is I380 NB On-Ramp over US 101 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 January 2024.

How much traffic does I380 NB On-Ramp over US 101 carry?

About 27,142 vehicles per day (2010 count), of which roughly 5% are trucks.

How long is I380 NB On-Ramp over US 101?

The structure is 1,325 ft (403.8 m) long with a longest span of 144 ft (44 m) and a deck 29 ft wide.

Who owns I380 NB On-Ramp over US 101?

It is owned by the Other Local Agency.