US Bridges

State Route 9 over San Lorenzo River

Fair

Santa Cruz County, California · 05-SCR-009-7.87 · Structure no. 36 0047

Built
1933
92 years old
Condition
Fair
inspected June 2024
Type
Arch - Deck
Concrete
Length
152 ft
1 main span
Daily traffic
21,100
2017 count
Owner
State
State Highway Agency

About this bridge

State Route 9 over San Lorenzo River is a concrete arch - deck carrying State Route 9 over San Lorenzo River in Santa Cruz County, California. It was built in 1933, so it is 92 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 21,100 vehicles a day, roughly 4% of them trucks, projected to reach 9,717 by 2046. The structure is 152 ft (46.2 m) long and 35 ft wide. If it were closed, the detour would be 5 mi (8 km).

CarriesState Route 9
CrossesSan Lorenzo River
Location05-SCR-009-7.87
RouteState Highway 9
Coordinates37.06957, -122.08396
Functional classUrban Minor 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.5 US tons
Inventory rating22.5 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1 (+5 approach)
Design loadH 15
Structure length152 ft (46.2 m)
Longest span105 ft (32 m)
Deck width35 ft (10.7 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,100 (2017)
Projected traffic9,717 by 2046
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was State Route 9 over San Lorenzo River built?

It was built in 1933, making it 92 years old in 2025.

What condition is State Route 9 over San Lorenzo River 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 June 2024.

How much traffic does State Route 9 over San Lorenzo River carry?

About 21,100 vehicles per day (2017 count), of which roughly 4% are trucks.

How long is State Route 9 over San Lorenzo River?

The structure is 152 ft (46.2 m) long with a longest span of 105 ft (32 m) and a deck 35 ft wide.

Who owns State Route 9 over San Lorenzo River?

It is owned by the State Highway Agency.