US Bridges

State Route 1 over Devil Slide

Fair

San Mateo County, California · 04-SM-001-R39.34-PFA · Structure no. 35 0331R

Built
2009
16 years old
Condition
Fair
inspected October 2024
Type
Segmental Box Girder
Prestressed Concrete
Length
904 ft
3 main spans
Daily traffic
14,500
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 1 over Devil Slide is a prestressed concrete segmental box girder carrying State Route 1 over Devil Slide in San Mateo County, California. It was built in 2009, so it is 16 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 14,500 vehicles a day, roughly 1% of them trucks, projected to reach 40,738 by 2042. The structure is 904 ft (275.4 m) long and 29 ft wide. If it were closed, the detour would be 23 mi (37 km).

Location

Open in Google Maps
CarriesState Route 1
CrossesDevil Slide
Location04-SM-001-R39.34-PFA
RouteState Highway 1
CountySan Mateo County
StateCalifornia
Coordinates37.58267, -122.50945
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 inspectionOctober 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 typeSegmental Box Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length904 ft (275.4 m)
Longest span448 ft (136.4 m)
Deck width29 ft (8.8 m)
Roadway width26 ft (7.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,500 (2009)
Projected traffic40,738 by 2042
Trucks1%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesOther
Detour if closed23 mi (37 km)
TollOn a free road
National Highway SystemYes

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 State Route 1 over Devil Slide built?

It was built in 2009, making it 16 years old in 2025.

What condition is State Route 1 over Devil Slide 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 October 2024.

How much traffic does State Route 1 over Devil Slide carry?

About 14,500 vehicles per day (2009 count), of which roughly 1% are trucks.

How long is State Route 1 over Devil Slide?

The structure is 904 ft (275.4 m) long with a longest span of 448 ft (136.4 m) and a deck 29 ft wide.

Who owns State Route 1 over Devil Slide?

It is owned by the State Highway Agency.