US Bridges

ROAD-1 South over R-1S Off-Ramp

Fair

San Mateo County, California · East of US 101 · Structure no. 35C0131S

Built
1973
52 years old
Condition
Fair
inspected January 2024
Type
Tee Beam
Prestressed Concrete
Length
40 ft
1 main span
Daily traffic
19,170
2010 count
Owner
City
City or Municipal Highway Agency

About this bridge

ROAD-1 South over R-1S Off-Ramp is a prestressed concrete tee beam carrying ROAD-1 South over R-1S Off-Ramp in San Mateo County, California. It was built in 1973, so it is 52 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 6 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 19,170 vehicles a day, roughly 5% of them trucks, projected to reach 30,034 by 2042. The structure is 40 ft (12.2 m) long and 43 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesROAD-1 South
CrossesR-1S Off-Ramp
LocationEast of US 101
RouteCity Street 0
CountySan Mateo County
StateCalifornia
Coordinates37.61531, -122.38878
Functional classUrban Other Principal Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment6: Equal to present minimum criteria
Operating rating37.5 US tons
Inventory rating35.7 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length40 ft (12.2 m)
Longest span36 ft (11 m)
Deck width43 ft (13 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deck15 ft (4.6 m)

Traffic and service

Average daily traffic19,170 (2010)
Projected traffic30,034 by 2042
Trucks5%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 ROAD-1 South over R-1S Off-Ramp built?

It was built in 1973, making it 52 years old in 2025.

What condition is ROAD-1 South over R-1S Off-Ramp 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 ROAD-1 South over R-1S Off-Ramp carry?

About 19,170 vehicles per day (2010 count), of which roughly 5% are trucks.

How long is ROAD-1 South over R-1S Off-Ramp?

The structure is 40 ft (12.2 m) long with a longest span of 36 ft (11 m) and a deck 43 ft wide.

Who owns ROAD-1 South over R-1S Off-Ramp?

It is owned by the City or Municipal Highway Agency.