US Bridges

State Route 1 over Elkhorn Slough

Fair

Monterey County, California · 05-MON-001-96.44 · Structure no. 44 0074

Built
1985
40 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
643 ft
10 main spans
Daily traffic
30,500
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 1 over Elkhorn Slough is a prestressed concrete continuous stringer/multi-beam or girder carrying State Route 1 over Elkhorn Slough in Monterey County, California. It was built in 1985, so it is 40 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 30,500 vehicles a day, roughly 10% of them trucks, projected to reach 34,492 by 2043. The structure is 643 ft (196 m) long and 52 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesState Route 1
CrossesElkhorn Slough
Location05-MON-001-96.44
RouteState Highway 1
CountyMonterey County
StateCalifornia
Coordinates36.80894, -121.78422
Functional classRural Principal Arterial - Other

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.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans10
Design loadHS 20 + Mod
Structure length643 ft (196 m)
Longest span64 ft (19.5 m)
Deck width52 ft (15.8 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30,500 (2009)
Projected traffic34,492 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed14.9 mi (24 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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was State Route 1 over Elkhorn Slough built?

It was built in 1985, making it 40 years old in 2025.

What condition is State Route 1 over Elkhorn Slough 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 August 2023.

How much traffic does State Route 1 over Elkhorn Slough carry?

About 30,500 vehicles per day (2009 count), of which roughly 10% are trucks.

How long is State Route 1 over Elkhorn Slough?

The structure is 643 ft (196 m) long with a longest span of 64 ft (19.5 m) and a deck 52 ft wide.

Who owns State Route 1 over Elkhorn Slough?

It is owned by the State Highway Agency.