US Bridges

State Route 9 over San Lorenzo River

Fair

Santa Cruz County, California · 05-SCR-009-7.76 · Structure no. 36 0046

Built
1927
98 years old
Condition
Fair
inspected June 2024
Type
Arch - Deck
Concrete
Length
305 ft
1 main span
Daily traffic
21,100
2009 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 1927, so it is 98 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 305 ft (92.9 m) long and 33 ft wide. If it were closed, the detour would be 5 mi (8 km).

CarriesState Route 9
CrossesSan Lorenzo River
Location05-SCR-009-7.76
RouteState Highway 9
Coordinates37.06822, -122.08276
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating31.4 US tons
Inventory rating19 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1 (+8 approach)
Design loadH 15
Structure length305 ft (92.9 m)
Longest span135 ft (41.1 m)
Deck width33 ft (10.2 m)
Roadway width21 ft (6.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,100 (2009)
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 1927, making it 98 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 (2009 count), of which roughly 4% are trucks.

How long is State Route 9 over San Lorenzo River?

The structure is 305 ft (92.9 m) long with a longest span of 135 ft (41.1 m) and a deck 33 ft wide.

Who owns State Route 9 over San Lorenzo River?

It is owned by the State Highway Agency.